diff --git a/content/base/src/nsSelection.cpp b/content/base/src/nsSelection.cpp
index 017047b67b36..f757840e29f2 100644
--- a/content/base/src/nsSelection.cpp
+++ b/content/base/src/nsSelection.cpp
@@ -1453,7 +1453,7 @@ nsDOMSelection::ToString(nsString& aReturn)
   PRInt32 cnt;
   GetRangeCount(&cnt);
   aReturn.AssignWithConversion("nsSelection: ");
-  aReturn += cnt;
+  aReturn.AppendInt(cnt);
   aReturn.AppendWithConversion(" items\n");
 
   // Get an iterator
@@ -1484,11 +1484,11 @@ nsDOMSelection::ToString(nsString& aReturn)
   PRInt32 theInt = (PRInt32)(nsIDOMNode*)FetchAnchorNode();
   aReturn.AppendWithConversion(theInt);
   aReturn.AppendWithConversion(", ");
-  aReturn += FetchAnchorOffset();
+  aReturn.AppendInt(FetchAnchorOffset());
   aReturn.AppendWithConversion("Focus is");
-  aReturn.AppendWithConversion((long)(nsIDOMNode*)FetchFocusNode(), 16);
+  aReturn.AppendInt((long)(nsIDOMNode*)FetchFocusNode(), 16);
   aReturn.AppendWithConversion(", ");
-  aReturn += FetchFocusOffset();
+  aReturn.AppendInt(FetchFocusOffset());
   aReturn.AppendWithConversion("\n ... end of selection\n");
 
   return NS_OK;
diff --git a/content/html/content/src/nsAttributeContent.cpp b/content/html/content/src/nsAttributeContent.cpp
index 6dde6287b295..961eee0ff679 100644
--- a/content/html/content/src/nsAttributeContent.cpp
+++ b/content/html/content/src/nsAttributeContent.cpp
@@ -460,7 +460,7 @@ nsAttributeContent::CopyText(nsString& aResult)
     aResult.Assign(mText.Get2b(), mText.GetLength());
   }
   else {
-    aResult.Assign(mText.Get1b(), mText.GetLength());
+    aResult.AssignWithConversion(mText.Get1b(), mText.GetLength());
   }
   return NS_OK;
 }
diff --git a/content/html/document/src/nsHTMLFragmentContentSink.cpp b/content/html/document/src/nsHTMLFragmentContentSink.cpp
index f76a26478784..3b02170d7bae 100644
--- a/content/html/document/src/nsHTMLFragmentContentSink.cpp
+++ b/content/html/document/src/nsHTMLFragmentContentSink.cpp
@@ -401,7 +401,7 @@ nsHTMLFragmentContentSink::OpenContainer(const nsIParserNode& aNode)
   nsAutoString tag;
   nsresult result = NS_OK;
 
-  tag = aNode.GetText();
+  tag.Assign(aNode.GetText());
   if (tag.EqualsIgnoreCase(kSentinelStr)) {
     mHitSentinel = PR_TRUE;
   }
@@ -806,7 +806,7 @@ nsHTMLFragmentContentSink::GetAttributeValueAt(const nsIParserNode& aNode,
             }
             *cp = '\0';
             PRInt32 ch;
-            nsAutoString str(cbuf);
+            nsAutoString str; str.AssignWithConversion(cbuf);
             dtd->ConvertEntityToUnicode(str, &ch);
             
             if (ch < 0) {
diff --git a/content/html/document/src/nsImageDocument.cpp b/content/html/document/src/nsImageDocument.cpp
index 41f9299d64b8..ae9a057f7beb 100644
--- a/content/html/document/src/nsImageDocument.cpp
+++ b/content/html/document/src/nsImageDocument.cpp
@@ -276,7 +276,9 @@ nsImageDocument::CreateSyntheticDocument()
 
   char* src;
   mDocumentURL->GetSpec(&src);
-  nsHTMLValue val(src);
+
+  nsString src_string; src_string.AssignWithConversion(src);
+  nsHTMLValue val(src_string);
   delete[] src;
   image->SetHTMLAttribute(nsHTMLAtoms::src, val, PR_FALSE);
   image->SetHTMLAttribute(nsHTMLAtoms::alt, val, PR_FALSE);
diff --git a/content/shared/src/nsXULAtoms.cpp b/content/shared/src/nsXULAtoms.cpp
index 9eed84f46e4f..653e4f1f20c0 100644
--- a/content/shared/src/nsXULAtoms.cpp
+++ b/content/shared/src/nsXULAtoms.cpp
@@ -47,7 +47,7 @@ void nsXULAtoms::AddRefAtoms() {
     */
     if (NS_SUCCEEDED(NS_NewNameSpaceManager(&gNameSpaceManager))) {
 //    gNameSpaceManager->CreateRootNameSpace(namespace);
-      nsAutoString nameSpace(kXULNameSpace);
+      nsAutoString nameSpace; nameSpace.AssignWithConversion(kXULNameSpace);
       gNameSpaceManager->RegisterNameSpace(nameSpace, nameSpaceID);
     } else {
       NS_ASSERTION(0, "failed to create xul atoms namespace manager");
diff --git a/content/xbl/src/nsXBLBinding.cpp b/content/xbl/src/nsXBLBinding.cpp
index 96bb42dcfa48..4125155b9d52 100644
--- a/content/xbl/src/nsXBLBinding.cpp
+++ b/content/xbl/src/nsXBLBinding.cpp
@@ -495,7 +495,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
     // in the excludes list.
     nsAutoString excludes;
     content->GetAttribute(kNameSpaceID_None, kExcludesAtom, excludes);
-    if (!excludes.Equals("*")) {
+    if (!excludes.EqualsWithConversion("*")) {
       if (!excludes.IsEmpty()) {
         // Walk the children and ensure that all of them
         // are in the excludes array.
@@ -540,7 +540,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
       nsCOMPtr<nsIDOMAttr> attr(do_QueryInterface(attribute));
       nsAutoString name;
       attr->GetName(name);
-      if (!name.Equals("excludes")) {
+      if (!name.EqualsWithConversion("excludes")) {
         nsAutoString value;
         nsCOMPtr<nsIDOMElement> element(do_QueryInterface(mBoundElement));
         element->GetAttribute(name, value);
@@ -616,7 +616,7 @@ nsXBLBinding::InstallEventHandlers(nsIContent* aBoundElement)
             PRBool useCapture = PR_FALSE;
             nsAutoString capturer;
             child->GetAttribute(kNameSpaceID_None, kCapturerAtom, capturer);
-            if (capturer.Equals("true"))
+            if (capturer.EqualsWithConversion("true"))
               useCapture = PR_TRUE;
 
             // Add the event listener.
@@ -742,8 +742,9 @@ nsXBLBinding::InstallProperties(nsIContent* aBoundElement)
         // and then define it as a property.
         if (!body.IsEmpty()) {
           void* myFunc;
+          nsCAutoString cname; cname.AssignWithConversion(name.GetUnicode());
           rv = context->CompileFunction(mScriptObject,
-                                        name,
+                                        cname,
                                         argCount,
                                         (const char**)args,
                                         body, 
@@ -769,7 +770,7 @@ nsXBLBinding::InstallProperties(nsIContent* aBoundElement)
           void* setFunc = nsnull;
           uintN attrs = 0;
 
-          if (readOnly.Equals("true"))
+          if (readOnly.EqualsWithConversion("true"))
             attrs |= JSPROP_READONLY;
 
           if (!getter.IsEmpty()) {
@@ -1139,7 +1140,7 @@ nsXBLBinding::IsInExcludesList(nsIAtom* aTag, const nsString& aList)
   nsAutoString element;
   aTag->ToString(element);
 
-  if (aList.Equals("*"))
+  if (aList.EqualsWithConversion("*"))
       return PR_TRUE; // match _everything_!
 
   PRInt32 indx = aList.Find(element);
@@ -1185,7 +1186,7 @@ nsXBLBinding::ConstructAttributeTable(nsIContent* aElement)
       nsCOMPtr<nsIAtom> attribute;
 
       // Figure out if this token contains a :. 
-      nsAutoString attr(token);
+      nsAutoString attr; attr.AssignWithConversion(token);
       PRInt32 index = attr.Find(":", PR_TRUE);
       if (index != -1) {
         // This attribute maps to something different.
@@ -1281,21 +1282,21 @@ nsXBLBinding::GetEventHandlerIID(nsIAtom* aName, nsIID* aIID, PRBool* aFound)
 PRBool
 nsXBLBinding::IsMouseHandler(const nsString& aName)
 {
-  return ((aName.Equals("click")) || (aName.Equals("dblclick")) || (aName.Equals("mousedown")) ||
-          (aName.Equals("mouseover")) || (aName.Equals("mouseout")) || (aName.Equals("mouseup")));
+  return ((aName.EqualsWithConversion("click")) || (aName.EqualsWithConversion("dblclick")) || (aName.EqualsWithConversion("mousedown")) ||
+          (aName.EqualsWithConversion("mouseover")) || (aName.EqualsWithConversion("mouseout")) || (aName.EqualsWithConversion("mouseup")));
 }
 
 PRBool
 nsXBLBinding::IsKeyHandler(const nsString& aName)
 {
-  return ((aName.Equals("keypress")) || (aName.Equals("keydown")) || (aName.Equals("keyup")));
+  return ((aName.EqualsWithConversion("keypress")) || (aName.EqualsWithConversion("keydown")) || (aName.EqualsWithConversion("keyup")));
 }
 
 PRBool
 nsXBLBinding::IsXULHandler(const nsString& aName)
 {
-  return ((aName.Equals("create")) || (aName.Equals("destroy")) || (aName.Equals("broadcast")) ||
-          (aName.Equals("command")) || (aName.Equals("commandupdate")) || (aName.Equals("close")));
+  return ((aName.EqualsWithConversion("create")) || (aName.EqualsWithConversion("destroy")) || (aName.EqualsWithConversion("broadcast")) ||
+          (aName.EqualsWithConversion("command")) || (aName.EqualsWithConversion("commandupdate")) || (aName.EqualsWithConversion("close")));
 }
 
 NS_IMETHODIMP
@@ -1304,7 +1305,7 @@ nsXBLBinding::AddScriptEventListener(nsIContent* aElement, nsIAtom* aName, const
   nsAutoString val;
   aName->ToString(val);
   
-  nsAutoString eventStr("on");
+  nsAutoString eventStr; eventStr.AssignWithConversion("on");
   eventStr += val;
 
   nsCOMPtr<nsIAtom> eventName = getter_AddRefs(NS_NewAtom(eventStr));
diff --git a/content/xbl/src/nsXBLEventHandler.cpp b/content/xbl/src/nsXBLEventHandler.cpp
index 18224baab385..711ea222972f 100644
--- a/content/xbl/src/nsXBLEventHandler.cpp
+++ b/content/xbl/src/nsXBLEventHandler.cpp
@@ -58,7 +58,7 @@ nsXBLEventHandler::nsXBLEventHandler(nsIContent* aBoundElement, nsIContent* aHan
   NS_INIT_REFCNT();
   mBoundElement = aBoundElement;
   mHandlerElement = aHandlerElement;
-  mEventName = aEventName;
+  mEventName.Assign(aEventName);
   gRefCnt++;
   if (gRefCnt == 1) {
     kKeyCodeAtom = NS_NewAtom("keycode");
@@ -101,154 +101,154 @@ nsresult nsXBLEventHandler::HandleEvent(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::KeyUp(nsIDOMEvent* aKeyEvent)
 {
-  if (!mEventName.Equals("keyup"))
+  if (!mEventName.EqualsWithConversion("keyup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
   if (KeyEventMatched(keyEvent))
-    ExecuteHandler(nsAutoString("keyup"), aKeyEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("keyup"), aKeyEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::KeyDown(nsIDOMEvent* aKeyEvent)
 {
-  if (!mEventName.Equals("keydown"))
+  if (!mEventName.EqualsWithConversion("keydown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
   if (KeyEventMatched(keyEvent))
-    ExecuteHandler(nsAutoString("keydown"), aKeyEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("keydown"), aKeyEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::KeyPress(nsIDOMEvent* aKeyEvent)
 {
-  if (!mEventName.Equals("keypress"))
+  if (!mEventName.EqualsWithConversion("keypress"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
   if (KeyEventMatched(keyEvent))
-    ExecuteHandler(nsAutoString("keypress"), aKeyEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("keypress"), aKeyEvent);
   return NS_OK;
 }
    
 nsresult nsXBLEventHandler::MouseDown(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mousedown"))
+  if (!mEventName.EqualsWithConversion("mousedown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mousedown"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mousedown"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseUp(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mouseup"))
+  if (!mEventName.EqualsWithConversion("mouseup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mouseup"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mouseup"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseClick(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("click"))
+  if (!mEventName.EqualsWithConversion("click"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("click"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("click"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseDblClick(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("dblclick"))
+  if (!mEventName.EqualsWithConversion("dblclick"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("dblclick"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("dblclick"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseOver(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mouseover"))
+  if (!mEventName.EqualsWithConversion("mouseover"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mouseover"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mouseover"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseOut(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mouseout"))
+  if (!mEventName.EqualsWithConversion("mouseout"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mouseout"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mouseout"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Action(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("command"))
+  if (!mEventName.EqualsWithConversion("command"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("command"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("command"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Create(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("create"))
+  if (!mEventName.EqualsWithConversion("create"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("create"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("create"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Close(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("close"))
+  if (!mEventName.EqualsWithConversion("close"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("close"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("close"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Broadcast(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("broadcast"))
+  if (!mEventName.EqualsWithConversion("broadcast"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("broadcast"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("broadcast"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::CommandUpdate(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("commandupdate"))
+  if (!mEventName.EqualsWithConversion("commandupdate"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("commandupdate"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("commandupdate"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Destroy(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("destroy"))
+  if (!mEventName.EqualsWithConversion("destroy"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("destroy"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("destroy"), aEvent);
   return NS_OK;
 }
 
@@ -257,8 +257,8 @@ nsresult nsXBLEventHandler::Destroy(nsIDOMEvent* aEvent)
 PRBool 
 nsXBLEventHandler::KeyEventMatched(nsIDOMKeyEvent* aKeyEvent)
 {
-  nsAutoString trueString = "true";
-  nsAutoString falseString = "false";
+  nsAutoString trueString; trueString.AssignWithConversion("true");
+  nsAutoString falseString; falseString.AssignWithConversion("false");
 
   // Get the keycode and charcode of the key event.
   PRUint32 keyCode, charCode;
@@ -272,12 +272,12 @@ nsXBLEventHandler::KeyEventMatched(nsIDOMKeyEvent* aKeyEvent)
   if (!key.IsEmpty())
     keyMatched = IsMatchingCharCode(charCode, key);
   
-  key = "";
+  key.SetLength(0);
   mHandlerElement->GetAttribute(kNameSpaceID_None, kKeyCodeAtom, key);
   if (!key.IsEmpty())
     keyMatched = IsMatchingKeyCode(keyCode, key);
   
-  key = "";
+  key.SetLength(0);
   mHandlerElement->GetAttribute(kNameSpaceID_None, kCharCodeAtom, key);
   if (!key.IsEmpty())
     keyMatched = IsMatchingCharCode(charCode, key);
@@ -374,8 +374,8 @@ nsXBLEventHandler::KeyEventMatched(nsIDOMKeyEvent* aKeyEvent)
 PRBool 
 nsXBLEventHandler::MouseEventMatched(nsIDOMUIEvent* aMouseEvent)
 {
-  nsAutoString trueString = "true";
-  nsAutoString falseString = "false";
+  nsAutoString trueString; trueString.AssignWithConversion("true");
+  nsAutoString falseString; falseString.AssignWithConversion("false");
 
   // XXX Check for button and modifier keys.
 
@@ -408,7 +408,7 @@ nsXBLEventHandler::ExecuteHandler(const nsString& aEventName, nsIDOMEvent* aEven
 
   // Look for a compiled handler on the element. 
   // Should be compiled and bound with "on" in front of the name.
-  nsAutoString onEvent = "onxbl";
+  nsAutoString onEvent; onEvent.AssignWithConversion("onxbl");
   onEvent += aEventName;
   nsCOMPtr<nsIAtom> onEventAtom = getter_AddRefs(NS_NewAtom(onEvent));
 
@@ -1066,7 +1066,7 @@ nsXBLEventHandler::IsMatchingCharCode(const PRUint32 aChar, const nsString& aKey
   char tempChar[2];
   tempChar[0] = aChar;
   tempChar[1] = 0;
-  nsAutoString tempChar2 = tempChar;
+  nsAutoString tempChar2; tempChar2.AssignWithConversion(tempChar);
   
   return tempChar2.EqualsIgnoreCase(aKeyName);
 }
diff --git a/content/xbl/src/nsXBLService.cpp b/content/xbl/src/nsXBLService.cpp
index c9d674c3faa9..2e3a0b7a3762 100644
--- a/content/xbl/src/nsXBLService.cpp
+++ b/content/xbl/src/nsXBLService.cpp
@@ -225,7 +225,7 @@ nsXBLService::nsXBLService(void)
     static const char kXBLNameSpaceURI[]
         = "http://www.mozilla.org/xbl";
 
-    rv = gNameSpaceManager->RegisterNameSpace(kXBLNameSpaceURI, kNameSpaceID_XBL);
+    rv = gNameSpaceManager->RegisterNameSpace(NS_ConvertASCIItoUCS2(kXBLNameSpaceURI), kNameSpaceID_XBL);
     NS_ASSERTION(NS_SUCCEEDED(rv), "unable to register XBL namespace");
     if (NS_FAILED(rv)) return;
 
@@ -272,7 +272,7 @@ nsXBLService::LoadBindings(nsIContent* aContent, const nsString& aURL)
 
   if (!binding) {
     nsCAutoString str = "Failed to locate XBL binding.  The invalid binding name is: ";
-    str += aURL;
+    str.AppendWithConversion(aURL);
     NS_ERROR(str);
     return NS_ERROR_FAILURE;
   }
@@ -403,7 +403,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
   if (!root)
     return NS_ERROR_FAILURE;
 
-  nsAutoString bindingName(ref);
+  nsAutoString bindingName; bindingName.AssignWithConversion( NS_STATIC_CAST(const char*, ref) );
 
   PRInt32 count;
   root->ChildCount(count);
diff --git a/content/xml/content/src/nsXMLCDATASection.cpp b/content/xml/content/src/nsXMLCDATASection.cpp
index 7cf0436274cb..b70b0edb103c 100644
--- a/content/xml/content/src/nsXMLCDATASection.cpp
+++ b/content/xml/content/src/nsXMLCDATASection.cpp
@@ -137,7 +137,7 @@ nsXMLCDATASection::GetTag(nsIAtom*& aResult) const
 NS_IMETHODIMP
 nsXMLCDATASection::GetNodeName(nsString& aNodeName)
 {
-  aNodeName.Assign("#cdata-section");
+  aNodeName.AssignWithConversion("#cdata-section");
   return NS_OK;
 }
 
diff --git a/content/xml/content/src/nsXMLElement.cpp b/content/xml/content/src/nsXMLElement.cpp
index 3e7eee011a46..ccad01016723 100644
--- a/content/xml/content/src/nsXMLElement.cpp
+++ b/content/xml/content/src/nsXMLElement.cpp
@@ -212,7 +212,7 @@ nsXMLElement::SetAttribute(PRInt32 aNameSpaceID, nsIAtom* aName,
   // to create an atom.
   if ((kNameSpaceID_XLink == aNameSpaceID) &&
       (kTypeAtom == aName)) { 
-    if (aValue.Equals(kSimpleAtom, PR_FALSE)) {
+    if (aValue.EqualsAtom(kSimpleAtom, PR_FALSE)) {
       // NOTE: This really is a link according to the XLink spec,
       //       we do not need to check other attributes. If there
       //       is no href attribute, then this link is simply
diff --git a/content/xml/content/src/nsXMLEntity.cpp b/content/xml/content/src/nsXMLEntity.cpp
index 25f0c548df55..66f2101893fd 100644
--- a/content/xml/content/src/nsXMLEntity.cpp
+++ b/content/xml/content/src/nsXMLEntity.cpp
@@ -266,19 +266,19 @@ nsXMLEntity::List(FILE* out, PRInt32 aIndent) const
 
   nsAutoString tmp(mName);
   if (mPublicId.Length()) {
-    tmp.Append(" PUBLIC \"");
+    tmp.AppendWithConversion(" PUBLIC \"");
     tmp.Append(mPublicId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   if (mSystemId.Length()) {
-    tmp.Append(" SYSTEM \"");
+    tmp.AppendWithConversion(" SYSTEM \"");
     tmp.Append(mSystemId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   if (mNotationName.Length()) {
-    tmp.Append(" NDATA ");
+    tmp.AppendWithConversion(" NDATA ");
     tmp.Append(mNotationName);
   }
 
diff --git a/content/xml/content/src/nsXMLNotation.cpp b/content/xml/content/src/nsXMLNotation.cpp
index 3edd362596ec..c9548d45a4dc 100644
--- a/content/xml/content/src/nsXMLNotation.cpp
+++ b/content/xml/content/src/nsXMLNotation.cpp
@@ -254,15 +254,15 @@ nsXMLNotation::List(FILE* out, PRInt32 aIndent) const
 
   nsAutoString tmp(mName);
   if (mPublicId.Length()) {
-    tmp.Append(" PUBLIC \"");
+    tmp.AppendWithConversion(" PUBLIC \"");
     tmp.Append(mPublicId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   if (mSystemId.Length()) {
-    tmp.Append(" SYSTEM \"");
+    tmp.AppendWithConversion(" SYSTEM \"");
     tmp.Append(mSystemId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   fputs(tmp, out);
diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index 91c478d384b0..7cd8ab661154 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -1342,7 +1342,7 @@ nsCSSFrameConstructor::CreateGeneratedContentFrame(nsIPresShell*        aPresShe
 
         nsCOMPtr<nsIDOMDocument> domdoc(do_QueryInterface(document));
         nsresult  result;
-        result = domdoc->CreateElement("SPAN",getter_AddRefs(containerElement));//is the literal the correct way?
+        result = domdoc->CreateElement(NS_ConvertASCIItoUCS2("SPAN"),getter_AddRefs(containerElement));//is the literal the correct way?
         if (NS_SUCCEEDED(result) && containerElement)
         {
           containerContent = do_QueryInterface(containerElement);
diff --git a/layout/base/src/nsSelection.cpp b/layout/base/src/nsSelection.cpp
index 017047b67b36..f757840e29f2 100644
--- a/layout/base/src/nsSelection.cpp
+++ b/layout/base/src/nsSelection.cpp
@@ -1453,7 +1453,7 @@ nsDOMSelection::ToString(nsString& aReturn)
   PRInt32 cnt;
   GetRangeCount(&cnt);
   aReturn.AssignWithConversion("nsSelection: ");
-  aReturn += cnt;
+  aReturn.AppendInt(cnt);
   aReturn.AppendWithConversion(" items\n");
 
   // Get an iterator
@@ -1484,11 +1484,11 @@ nsDOMSelection::ToString(nsString& aReturn)
   PRInt32 theInt = (PRInt32)(nsIDOMNode*)FetchAnchorNode();
   aReturn.AppendWithConversion(theInt);
   aReturn.AppendWithConversion(", ");
-  aReturn += FetchAnchorOffset();
+  aReturn.AppendInt(FetchAnchorOffset());
   aReturn.AppendWithConversion("Focus is");
-  aReturn.AppendWithConversion((long)(nsIDOMNode*)FetchFocusNode(), 16);
+  aReturn.AppendInt((long)(nsIDOMNode*)FetchFocusNode(), 16);
   aReturn.AppendWithConversion(", ");
-  aReturn += FetchFocusOffset();
+  aReturn.AppendInt(FetchFocusOffset());
   aReturn.AppendWithConversion("\n ... end of selection\n");
 
   return NS_OK;
diff --git a/layout/build/nsLayoutModule.cpp b/layout/build/nsLayoutModule.cpp
index 27321f94d7ec..c67e66ace329 100644
--- a/layout/build/nsLayoutModule.cpp
+++ b/layout/build/nsLayoutModule.cpp
@@ -424,7 +424,8 @@ nsLayoutModule::CanUnload(nsIComponentManager *aCompMgr, PRBool *okToUnload)
 void
 nsLayoutModule::SetUserAgent( void )
 {
-  nsString productName(PRODUCT_NAME), productVersion(PRODUCT_VERSION);
+  nsString productName; productName.AssignWithConversion(PRODUCT_NAME);
+  nsString productVersion; productVersion.AssignWithConversion(PRODUCT_VERSION);
   nsresult rv = nsnull;
 
   nsCOMPtr<nsIHTTPProtocolHandler> theService(do_GetService(kHTTPHandlerCID,
diff --git a/layout/forms/nsButtonFrameRenderer.cpp b/layout/forms/nsButtonFrameRenderer.cpp
index cbef2938c017..d90e7a13c82b 100644
--- a/layout/forms/nsButtonFrameRenderer.cpp
+++ b/layout/forms/nsButtonFrameRenderer.cpp
@@ -78,7 +78,7 @@ nsButtonFrameRenderer::SetDisabled(PRBool aDisabled, PRBool notify)
   mFrame->GetContent(getter_AddRefs(content));
 
   if (aDisabled)
-    content->SetAttribute(mNameSpace, nsHTMLAtoms::disabled, "", notify);
+    content->SetAttribute(mNameSpace, nsHTMLAtoms::disabled, nsAutoString(), notify);
   else
     content->UnsetAttribute(mNameSpace, nsHTMLAtoms::disabled, notify);
 
diff --git a/layout/forms/nsComboboxControlFrame.cpp b/layout/forms/nsComboboxControlFrame.cpp
index 71ba1e681127..eeec58df6326 100644
--- a/layout/forms/nsComboboxControlFrame.cpp
+++ b/layout/forms/nsComboboxControlFrame.cpp
@@ -223,7 +223,6 @@ nsComboboxControlFrame::nsComboboxControlFrame()
   mPresContext                 = nsnull;
   mFormFrame                   = nsnull;       
   mListControlFrame            = nsnull;
-  mTextStr                     = "";
   mButtonContent               = nsnull;
   mDroppedDown                 = PR_FALSE;
   mDisplayFrame                = nsnull;
@@ -337,7 +336,7 @@ nsComboboxControlFrame::MakeSureSomethingIsSelected(nsIPresContext* aPresContext
       mListControlFrame->GetNumberOfOptions(&length);
       if (length > 0) {
          // Set listbox selection to first item in the list box
-        rv = fcFrame->SetProperty(aPresContext, nsHTMLAtoms::selectedindex, "0");
+        rv = fcFrame->SetProperty(aPresContext, nsHTMLAtoms::selectedindex, NS_ConvertASCIItoUCS2("0"));
         mSelectedIndex = 0;
       } else {
         UpdateSelection(PR_FALSE, PR_TRUE, mSelectedIndex); // Needed to reflow when removing last option
@@ -494,7 +493,7 @@ nsComboboxControlFrame::ShowPopup(PRBool aShowPopup)
   
   nsCOMPtr<nsIAtom> activeAtom ( dont_QueryInterface(NS_NewAtom(kMozDropdownActive)));
   if (PR_TRUE == aShowPopup) {
-    mContent->SetAttribute(kNameSpaceID_None, activeAtom, "", PR_TRUE);
+    mContent->SetAttribute(kNameSpaceID_None, activeAtom, nsAutoString(), PR_TRUE);
   } else {
     mContent->UnsetAttribute(kNameSpaceID_None, activeAtom, PR_TRUE);
   }
@@ -2085,7 +2084,7 @@ nsComboboxControlFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
   // Add a child text content node for the label
   nsCOMPtr<nsIContent> labelContent;
   nsresult result = NS_NewTextNode(getter_AddRefs(labelContent));
-  nsAutoString value="X";
+  nsAutoString value; value.AssignWithConversion("X");
   if (NS_SUCCEEDED(result) && labelContent) {
     // set the value of the text node
     mDisplayContent = do_QueryInterface(labelContent);
@@ -2101,7 +2100,7 @@ nsComboboxControlFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
     result = NS_NewHTMLInputElement(&mButtonContent, nsHTMLAtoms::input);
     //NS_ADDREF(mButtonContent);
     if (NS_SUCCEEDED(result) && mButtonContent) {
-      mButtonContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::type, nsAutoString("button"), PR_FALSE);
+      mButtonContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::type, NS_ConvertASCIItoUCS2("button"), PR_FALSE);
       aChildList.AppendElement(mButtonContent);
     }
   }
diff --git a/layout/forms/nsFileControlFrame.cpp b/layout/forms/nsFileControlFrame.cpp
index 74319b46ba77..d2882faf5644 100644
--- a/layout/forms/nsFileControlFrame.cpp
+++ b/layout/forms/nsFileControlFrame.cpp
@@ -249,8 +249,8 @@ nsFileControlFrame::MouseClick(nsIDOMEvent* aMouseEvent)
   nsComponentManager::CreateInstance(kCFileWidgetCID, nsnull, kIFileWidgetIID, (void**)&fileWidget);
   
   if (fileWidget) {
-    nsString titles[] = {"all files"};
-    nsString filters[] = {"*.*"};
+    nsString titles[1]; titles[0].AssignWithConversion("all files");
+    nsString filters[1]; filters[0].AssignWithConversion("*.*");
     fileWidget->SetFilterList(1, titles, filters);
 
     fileWidget->Create(parentWidget, title, eMode_load, nsnull, nsnull);
diff --git a/layout/forms/nsFormControlHelper.cpp b/layout/forms/nsFormControlHelper.cpp
index b28357ec572d..20e07a32a864 100644
--- a/layout/forms/nsFormControlHelper.cpp
+++ b/layout/forms/nsFormControlHelper.cpp
@@ -112,26 +112,20 @@ void nsFormControlHelper::ForceDrawFrame(nsIPresContext* aPresContext, nsIFrame
 void nsFormControlHelper::PlatformToDOMLineBreaks(nsString &aString)
 {
   // Windows linebreaks: Map CRLF to LF:
-  aString.ReplaceSubstring("\r\n", "\n");
+  aString.ReplaceSubstring(NS_ConvertASCIItoUCS2("\r\n"), NS_ConvertASCIItoUCS2("\n"));
 
   // Mac linebreaks: Map any remaining CR to LF:
-  aString.ReplaceSubstring("\r", "\n");
+  aString.ReplaceSubstring(NS_ConvertASCIItoUCS2("\r"), NS_ConvertASCIItoUCS2("\n"));
 }
 
 PRBool nsFormControlHelper::GetBool(const nsString& aValue)
 {
-  if (aValue.Equals(NS_STRING_TRUE))
-    return(PR_TRUE);
-  else
-    return (PR_FALSE);
+  return aValue.EqualsWithConversion(NS_STRING_TRUE);
 }
 
 void nsFormControlHelper::GetBoolString(const PRBool aValue, nsString& aResult)
 {
-  if (PR_TRUE == aValue)
-    aResult = NS_STRING_TRUE;
-  else
-    aResult = NS_STRING_FALSE;
+  aResult.AssignWithConversion( aValue ? NS_STRING_TRUE : NS_STRING_FALSE );
 }
 
 
@@ -172,7 +166,7 @@ nsresult nsFormControlHelper::GetFrameFontFM(nsIPresContext* aPresContext,
 nsresult
 nsFormControlHelper::GetWrapProperty(nsIContent * aContent, nsString &aOutValue)
 {
-  aOutValue = "";
+  aOutValue.SetLength(0);
   nsresult result = NS_CONTENT_ATTR_NOT_THERE;
   nsIHTMLContent* content = nsnull;
   aContent->QueryInterface(kIHTMLContentIID, (void**) &content);
@@ -198,16 +192,16 @@ nsFormControlHelper::GetWrapPropertyEnum(nsIContent * aContent, nsHTMLTextWrap&
 
   if (NS_CONTENT_ATTR_NOT_THERE != result) {
 
-    nsAutoString wrapHard(kTextControl_Wrap_Hard);
-    nsAutoString wrapPhysical(kTextControl_Wrap_Physical);
+    nsAutoString wrapHard; wrapHard.AssignWithConversion(kTextControl_Wrap_Hard);
+    nsAutoString wrapPhysical; wrapPhysical.AssignWithConversion(kTextControl_Wrap_Physical);
     if (wrap.EqualsIgnoreCase(wrapHard) ||
         wrap.EqualsIgnoreCase(wrapPhysical)) {
       aWrapProp = eHTMLTextWrap_Hard;
       return result;
     }
 
-    nsAutoString wrapSoft(kTextControl_Wrap_Soft);
-    nsAutoString wrapVirtual(kTextControl_Wrap_Virtual);
+    nsAutoString wrapSoft; wrapSoft.AssignWithConversion(kTextControl_Wrap_Soft);
+    nsAutoString wrapVirtual; wrapVirtual.AssignWithConversion(kTextControl_Wrap_Virtual);
     if (wrap.EqualsIgnoreCase(wrapSoft) ||
         wrap.EqualsIgnoreCase(wrapVirtual)) {
       aWrapProp = eHTMLTextWrap_Soft;
@@ -384,10 +378,10 @@ nsFormControlHelper::GetTextSize(nsIPresContext* aPresContext, nsIFormControlFra
   GetRepChars(aPresContext, char1, char2);
   int i;
   for (i = 0; i < aNumChars; i+=2) {
-    val += char1;  
+    val.AppendWithConversion(char1);  
   }
   for (i = 1; i < aNumChars; i+=2) {
-    val += char2;  
+    val.AppendWithConversion(char2);  
   }
   return GetTextSize(aPresContext, aFrame, val, aSize, aRendContext);
 }
diff --git a/layout/forms/nsGfxButtonControlFrame.cpp b/layout/forms/nsGfxButtonControlFrame.cpp
index 2c7f3aecf6c9..c760f8073d93 100644
--- a/layout/forms/nsGfxButtonControlFrame.cpp
+++ b/layout/forms/nsGfxButtonControlFrame.cpp
@@ -250,7 +250,7 @@ nsGfxButtonControlFrame::DoNavQuirksReflow(nsIPresContext*          aPresContext
     if (!textStyle->WhiteSpaceIsSignificant()) {
       value.CompressWhitespace();
       if (value.Length() == 0) {
-        value = "  ";
+        value.AssignWithConversion("  ");
       }
     }
 
@@ -384,7 +384,7 @@ nsGfxButtonControlFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
   if (!textStyle->WhiteSpaceIsSignificant()) {
     value.CompressWhitespace();
     if (value.Length() == 0) {
-      value = "  ";
+      value.AssignWithConversion("  ");
     }
   }
 
@@ -438,7 +438,7 @@ nsGfxButtonControlFrame::GetDefaultLabel(nsString& aString)
     rv = ButtonLocalize("Browse", aString);
   }
   else {
-    aString = "  ";
+    aString.AssignWithConversion("  ");
     rv = NS_OK;
   }
   return rv;
@@ -478,7 +478,7 @@ nsGfxButtonControlFrame::ButtonLocalize(char* aKey, nsString& oVal)
   // Determine default label from string bundle
   if (NS_SUCCEEDED(rv) && bundle && aKey) {
     nsXPIDLString valUni;
-    nsAutoString key(aKey);
+    nsAutoString key; key.AssignWithConversion(aKey);
     rv = bundle->GetStringFromName(key.GetUnicode(), getter_Copies(valUni));
     if (NS_SUCCEEDED(rv) && valUni) {
       oVal.Assign(valUni);
@@ -503,7 +503,7 @@ nsGfxButtonControlFrame::AttributeChanged(nsIPresContext* aPresContext,
     nsAutoString value;
     if (mTextContent && mContent) {
       if (NS_CONTENT_ATTR_HAS_VALUE != mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::value, value)) {
-        value = "";
+        value.SetLength(0);
       }
       rv = mTextContent->SetText(value.GetUnicode(), value.Length(), PR_TRUE);
     } else {
diff --git a/layout/forms/nsGfxCheckboxControlFrame.cpp b/layout/forms/nsGfxCheckboxControlFrame.cpp
index b1f766add59b..ba60057b8451 100644
--- a/layout/forms/nsGfxCheckboxControlFrame.cpp
+++ b/layout/forms/nsGfxCheckboxControlFrame.cpp
@@ -119,7 +119,7 @@ nsGfxCheckboxControlFrame::Init(nsIPresContext*  aPresContext,
 
   // give the attribute a default value so it's always present, if we're a tristate
   if ( IsTristateCheckbox() )
-    mContent->SetAttribute ( kNameSpaceID_None, GetTristateValueAtom(), "0", PR_FALSE );
+    mContent->SetAttribute ( kNameSpaceID_None, GetTristateValueAtom(), NS_ConvertASCIItoUCS2("0"), PR_FALSE );
   
   return NS_OK;
 }
@@ -494,7 +494,7 @@ nsGfxCheckboxControlFrame::GetNamesValues(PRInt32 aMaxNumValues, PRInt32& aNumVa
       result = PR_FALSE;
    } else {
      if (NS_CONTENT_ATTR_HAS_VALUE != valueResult) {
-       aValues[0] = "on";
+       aValues[0].AssignWithConversion("on");
      } else {
        aValues[0] = value;
      }
@@ -526,15 +526,15 @@ nsGfxCheckboxControlFrame::CheckStateToString ( CheckState inState, nsString& ou
 {
   switch ( inState ) {
     case eOn:
-      outStateAsString = NS_STRING_TRUE;
+      outStateAsString.AssignWithConversion(NS_STRING_TRUE);
 	  break;
 
     case eOff:
-      outStateAsString = NS_STRING_FALSE;
+      outStateAsString.AssignWithConversion(NS_STRING_FALSE);
       break;
  
     case eMixed:
-      outStateAsString = "2";
+      outStateAsString.AssignWithConversion("2");
       break;
   }
 } // CheckStateToString
@@ -549,9 +549,9 @@ nsGfxCheckboxControlFrame::CheckStateToString ( CheckState inState, nsString& ou
 nsGfxCheckboxControlFrame::CheckState 
 nsGfxCheckboxControlFrame::StringToCheckState ( const nsString & aStateAsString )
 {
-  if ( aStateAsString.Equals(NS_STRING_TRUE) )
+  if ( aStateAsString.EqualsWithConversion(NS_STRING_TRUE) )
     return eOn;
-  else if ( aStateAsString.Equals(NS_STRING_FALSE) )
+  else if ( aStateAsString.EqualsWithConversion(NS_STRING_FALSE) )
     return eOff;
 
   // not true and not false means mixed
@@ -614,7 +614,7 @@ NS_IMETHODIMP nsGfxCheckboxControlFrame::SaveState(nsIPresContext* aPresContext,
   // This string will hold a single item, whether or not we're checked.
   nsAutoString stateString;
   GetCheckboxControlFrameState(stateString);
-  (*aState)->SetStateProperty("checked", stateString);
+  (*aState)->SetStateProperty(NS_ConvertASCIItoUCS2("checked"), stateString);
 
   return NS_OK;
 }
@@ -628,7 +628,7 @@ NS_IMETHODIMP nsGfxCheckboxControlFrame::RestoreState(nsIPresContext* aPresConte
     mDidInit = PR_TRUE;
   }
   nsAutoString string;
-  aState->GetStateProperty("checked", string);
+  aState->GetStateProperty(NS_ConvertASCIItoUCS2("checked"), string);
   SetCheckboxControlFrameState(aPresContext, string);
   return NS_OK;
 }
diff --git a/layout/forms/nsGfxRadioControlFrame.cpp b/layout/forms/nsGfxRadioControlFrame.cpp
index 3421411658c0..f121b4d4c4db 100644
--- a/layout/forms/nsGfxRadioControlFrame.cpp
+++ b/layout/forms/nsGfxRadioControlFrame.cpp
@@ -125,7 +125,7 @@ nsGfxRadioControlFrame::SetAdditionalStyleContext(PRInt32 aIndex,
 NS_IMETHODIMP nsGfxRadioControlFrame::SetProperty(nsIPresContext* aPresContext, nsIAtom* aName, const nsString& aValue)
 {
   if (nsHTMLAtoms::checked == aName) {
-    PRBool state = (aValue.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
+    PRBool state = (aValue.EqualsWithConversion(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
 
     // if there is no form than the radiobtn is an orphan
@@ -185,9 +185,9 @@ nsGfxRadioControlFrame::SetChecked(nsIPresContext* aPresContext, PRBool aValue,
 {
   if (aSetInitialValue) {
     if (aValue) {
-      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, nsAutoString("1"), PR_FALSE); // XXX should be "empty" value
+      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, NS_ConvertASCIItoUCS2("1"), PR_FALSE); // XXX should be "empty" value
     } else {
-      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, nsAutoString("0"), PR_FALSE);
+      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, NS_ConvertASCIItoUCS2("0"), PR_FALSE);
     }
   }
 
@@ -226,7 +226,7 @@ nsGfxRadioControlFrame::GetNamesValues(PRInt32 aMaxNumValues, PRInt32& aNumValue
   if (NS_CONTENT_ATTR_HAS_VALUE == result) {
     aValues[0] = value;
   } else {
-    aValues[0] = "on";
+    aValues[0].AssignWithConversion("on");
   }
   aNames[0]  = name;
   aNumValues = 1;
@@ -345,7 +345,7 @@ nsGfxRadioControlFrame::SaveState(nsIPresContext* aPresContext, nsIPresState** a
   // This string will hold a single item, whether or not we're checked.
   nsAutoString stateString;
 	nsFormControlHelper::GetBoolString(GetRadioState(), stateString);
-  (*aState)->SetStateProperty("checked", stateString);
+  (*aState)->SetStateProperty(NS_ConvertASCIItoUCS2("checked"), stateString);
 
   return NS_OK;
 }
@@ -364,8 +364,8 @@ nsGfxRadioControlFrame::RestoreState(nsIPresContext* aPresContext, nsIPresState*
 
   mIsRestored = PR_TRUE;
   nsAutoString string;
-  aState->GetStateProperty("checked", string);
-  PRBool state = (string.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
+  aState->GetStateProperty(NS_ConvertASCIItoUCS2("checked"), string);
+  PRBool state = (string.EqualsWithConversion(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
   SetRadioState(aPresContext, state); // sets mChecked
   mRestoredChecked = mChecked;
diff --git a/layout/forms/nsListControlFrame.cpp b/layout/forms/nsListControlFrame.cpp
index 1887624496a2..785e4b447af4 100644
--- a/layout/forms/nsListControlFrame.cpp
+++ b/layout/forms/nsListControlFrame.cpp
@@ -910,10 +910,10 @@ nsListControlFrame::DisplaySelected(nsIContent* aContent)
    // The event state manager supports selected states. KMM
   
   if (PR_TRUE == mIsAllFramesHere) {
-    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, "", PR_TRUE);
+    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, nsAutoString(), PR_TRUE);
     //ForceRedraw();
   } else {
-    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, "", PR_FALSE);
+    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, nsAutoString(), PR_FALSE);
   }
 }
 
@@ -1770,7 +1770,7 @@ nsListControlFrame::Reset(nsIPresContext* aPresContext)
   // Ok, so we were restored, now set the last known selections from the restore state.
   if (hasBeenRestored) {
     nsCOMPtr<nsISupports> supp;
-    mPresState->GetStatePropertyAsSupports("selecteditems", getter_AddRefs(supp));
+    mPresState->GetStatePropertyAsSupports(NS_ConvertASCIItoUCS2("selecteditems"), getter_AddRefs(supp));
 
     nsresult res = NS_ERROR_NULL_POINTER;
     if (!supp)
@@ -1949,7 +1949,7 @@ nsListControlFrame::SetComboboxFrame(nsIFrame* aComboboxFrame)
 NS_IMETHODIMP 
 nsListControlFrame::GetSelectedItem(nsString & aStr)
 {
-  aStr = "";
+  aStr.SetLength(0);
   nsresult rv = NS_ERROR_FAILURE; 
   nsCOMPtr<nsIDOMHTMLCollection> options = getter_AddRefs(GetOptions(mContent));
 
@@ -2429,7 +2429,7 @@ nsListControlFrame::GetProperty(nsIAtom* aName, nsString& aValue)
     if ((kNothingSelected == selectedIndex) && (mComboboxFrame)) {
       selectedIndex = 0;
     }
-    aValue.Append(selectedIndex, 10);
+    aValue.AppendInt(selectedIndex, 10);
   }
 
   return NS_OK;
@@ -3364,7 +3364,7 @@ nsListControlFrame::SaveStateInternal(nsIPresContext* aPresContext, nsIPresState
   }
   
   NS_NewPresState(aState);
-  (*aState)->SetStatePropertyAsSupports("selecteditems", value);
+  (*aState)->SetStatePropertyAsSupports(NS_ConvertASCIItoUCS2("selecteditems"), value);
   return res;
 }
 
diff --git a/layout/generic/nsBulletFrame.cpp b/layout/generic/nsBulletFrame.cpp
index e97c4043a551..f8401e537825 100644
--- a/layout/generic/nsBulletFrame.cpp
+++ b/layout/generic/nsBulletFrame.cpp
@@ -289,12 +289,12 @@ static void RomanToText(PRInt32 ordinal, nsString& result, const char* achars, c
       case '7': case  '8':
         addOn.AppendWithConversion(bchars[romanPos]);
         for(n=0;n<(*dp-'5');n++) {
-          addOn.Append(achars[romanPos]);
+          addOn.AppendWithConversion(achars[romanPos]);
         }
         break;
       case '9':
-        addOn.Append(achars[romanPos]);
-        addOn.Append(achars[romanPos+1]);
+        addOn.AppendWithConversion(achars[romanPos]);
+        addOn.AppendWithConversion(achars[romanPos+1]);
         break;
       default:
         break;
diff --git a/layout/generic/nsSelection.cpp b/layout/generic/nsSelection.cpp
index 017047b67b36..f757840e29f2 100644
--- a/layout/generic/nsSelection.cpp
+++ b/layout/generic/nsSelection.cpp
@@ -1453,7 +1453,7 @@ nsDOMSelection::ToString(nsString& aReturn)
   PRInt32 cnt;
   GetRangeCount(&cnt);
   aReturn.AssignWithConversion("nsSelection: ");
-  aReturn += cnt;
+  aReturn.AppendInt(cnt);
   aReturn.AppendWithConversion(" items\n");
 
   // Get an iterator
@@ -1484,11 +1484,11 @@ nsDOMSelection::ToString(nsString& aReturn)
   PRInt32 theInt = (PRInt32)(nsIDOMNode*)FetchAnchorNode();
   aReturn.AppendWithConversion(theInt);
   aReturn.AppendWithConversion(", ");
-  aReturn += FetchAnchorOffset();
+  aReturn.AppendInt(FetchAnchorOffset());
   aReturn.AppendWithConversion("Focus is");
-  aReturn.AppendWithConversion((long)(nsIDOMNode*)FetchFocusNode(), 16);
+  aReturn.AppendInt((long)(nsIDOMNode*)FetchFocusNode(), 16);
   aReturn.AppendWithConversion(", ");
-  aReturn += FetchFocusOffset();
+  aReturn.AppendInt(FetchFocusOffset());
   aReturn.AppendWithConversion("\n ... end of selection\n");
 
   return NS_OK;
diff --git a/layout/html/base/src/nsBulletFrame.cpp b/layout/html/base/src/nsBulletFrame.cpp
index e97c4043a551..f8401e537825 100644
--- a/layout/html/base/src/nsBulletFrame.cpp
+++ b/layout/html/base/src/nsBulletFrame.cpp
@@ -289,12 +289,12 @@ static void RomanToText(PRInt32 ordinal, nsString& result, const char* achars, c
       case '7': case  '8':
         addOn.AppendWithConversion(bchars[romanPos]);
         for(n=0;n<(*dp-'5');n++) {
-          addOn.Append(achars[romanPos]);
+          addOn.AppendWithConversion(achars[romanPos]);
         }
         break;
       case '9':
-        addOn.Append(achars[romanPos]);
-        addOn.Append(achars[romanPos+1]);
+        addOn.AppendWithConversion(achars[romanPos]);
+        addOn.AppendWithConversion(achars[romanPos+1]);
         break;
       default:
         break;
diff --git a/layout/html/content/src/nsAttributeContent.cpp b/layout/html/content/src/nsAttributeContent.cpp
index 6dde6287b295..961eee0ff679 100644
--- a/layout/html/content/src/nsAttributeContent.cpp
+++ b/layout/html/content/src/nsAttributeContent.cpp
@@ -460,7 +460,7 @@ nsAttributeContent::CopyText(nsString& aResult)
     aResult.Assign(mText.Get2b(), mText.GetLength());
   }
   else {
-    aResult.Assign(mText.Get1b(), mText.GetLength());
+    aResult.AssignWithConversion(mText.Get1b(), mText.GetLength());
   }
   return NS_OK;
 }
diff --git a/layout/html/document/src/nsHTMLFragmentContentSink.cpp b/layout/html/document/src/nsHTMLFragmentContentSink.cpp
index f76a26478784..3b02170d7bae 100644
--- a/layout/html/document/src/nsHTMLFragmentContentSink.cpp
+++ b/layout/html/document/src/nsHTMLFragmentContentSink.cpp
@@ -401,7 +401,7 @@ nsHTMLFragmentContentSink::OpenContainer(const nsIParserNode& aNode)
   nsAutoString tag;
   nsresult result = NS_OK;
 
-  tag = aNode.GetText();
+  tag.Assign(aNode.GetText());
   if (tag.EqualsIgnoreCase(kSentinelStr)) {
     mHitSentinel = PR_TRUE;
   }
@@ -806,7 +806,7 @@ nsHTMLFragmentContentSink::GetAttributeValueAt(const nsIParserNode& aNode,
             }
             *cp = '\0';
             PRInt32 ch;
-            nsAutoString str(cbuf);
+            nsAutoString str; str.AssignWithConversion(cbuf);
             dtd->ConvertEntityToUnicode(str, &ch);
             
             if (ch < 0) {
diff --git a/layout/html/document/src/nsImageDocument.cpp b/layout/html/document/src/nsImageDocument.cpp
index 41f9299d64b8..ae9a057f7beb 100644
--- a/layout/html/document/src/nsImageDocument.cpp
+++ b/layout/html/document/src/nsImageDocument.cpp
@@ -276,7 +276,9 @@ nsImageDocument::CreateSyntheticDocument()
 
   char* src;
   mDocumentURL->GetSpec(&src);
-  nsHTMLValue val(src);
+
+  nsString src_string; src_string.AssignWithConversion(src);
+  nsHTMLValue val(src_string);
   delete[] src;
   image->SetHTMLAttribute(nsHTMLAtoms::src, val, PR_FALSE);
   image->SetHTMLAttribute(nsHTMLAtoms::alt, val, PR_FALSE);
diff --git a/layout/html/forms/src/nsButtonFrameRenderer.cpp b/layout/html/forms/src/nsButtonFrameRenderer.cpp
index cbef2938c017..d90e7a13c82b 100644
--- a/layout/html/forms/src/nsButtonFrameRenderer.cpp
+++ b/layout/html/forms/src/nsButtonFrameRenderer.cpp
@@ -78,7 +78,7 @@ nsButtonFrameRenderer::SetDisabled(PRBool aDisabled, PRBool notify)
   mFrame->GetContent(getter_AddRefs(content));
 
   if (aDisabled)
-    content->SetAttribute(mNameSpace, nsHTMLAtoms::disabled, "", notify);
+    content->SetAttribute(mNameSpace, nsHTMLAtoms::disabled, nsAutoString(), notify);
   else
     content->UnsetAttribute(mNameSpace, nsHTMLAtoms::disabled, notify);
 
diff --git a/layout/html/forms/src/nsComboboxControlFrame.cpp b/layout/html/forms/src/nsComboboxControlFrame.cpp
index 71ba1e681127..eeec58df6326 100644
--- a/layout/html/forms/src/nsComboboxControlFrame.cpp
+++ b/layout/html/forms/src/nsComboboxControlFrame.cpp
@@ -223,7 +223,6 @@ nsComboboxControlFrame::nsComboboxControlFrame()
   mPresContext                 = nsnull;
   mFormFrame                   = nsnull;       
   mListControlFrame            = nsnull;
-  mTextStr                     = "";
   mButtonContent               = nsnull;
   mDroppedDown                 = PR_FALSE;
   mDisplayFrame                = nsnull;
@@ -337,7 +336,7 @@ nsComboboxControlFrame::MakeSureSomethingIsSelected(nsIPresContext* aPresContext
       mListControlFrame->GetNumberOfOptions(&length);
       if (length > 0) {
          // Set listbox selection to first item in the list box
-        rv = fcFrame->SetProperty(aPresContext, nsHTMLAtoms::selectedindex, "0");
+        rv = fcFrame->SetProperty(aPresContext, nsHTMLAtoms::selectedindex, NS_ConvertASCIItoUCS2("0"));
         mSelectedIndex = 0;
       } else {
         UpdateSelection(PR_FALSE, PR_TRUE, mSelectedIndex); // Needed to reflow when removing last option
@@ -494,7 +493,7 @@ nsComboboxControlFrame::ShowPopup(PRBool aShowPopup)
   
   nsCOMPtr<nsIAtom> activeAtom ( dont_QueryInterface(NS_NewAtom(kMozDropdownActive)));
   if (PR_TRUE == aShowPopup) {
-    mContent->SetAttribute(kNameSpaceID_None, activeAtom, "", PR_TRUE);
+    mContent->SetAttribute(kNameSpaceID_None, activeAtom, nsAutoString(), PR_TRUE);
   } else {
     mContent->UnsetAttribute(kNameSpaceID_None, activeAtom, PR_TRUE);
   }
@@ -2085,7 +2084,7 @@ nsComboboxControlFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
   // Add a child text content node for the label
   nsCOMPtr<nsIContent> labelContent;
   nsresult result = NS_NewTextNode(getter_AddRefs(labelContent));
-  nsAutoString value="X";
+  nsAutoString value; value.AssignWithConversion("X");
   if (NS_SUCCEEDED(result) && labelContent) {
     // set the value of the text node
     mDisplayContent = do_QueryInterface(labelContent);
@@ -2101,7 +2100,7 @@ nsComboboxControlFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
     result = NS_NewHTMLInputElement(&mButtonContent, nsHTMLAtoms::input);
     //NS_ADDREF(mButtonContent);
     if (NS_SUCCEEDED(result) && mButtonContent) {
-      mButtonContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::type, nsAutoString("button"), PR_FALSE);
+      mButtonContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::type, NS_ConvertASCIItoUCS2("button"), PR_FALSE);
       aChildList.AppendElement(mButtonContent);
     }
   }
diff --git a/layout/html/forms/src/nsFileControlFrame.cpp b/layout/html/forms/src/nsFileControlFrame.cpp
index 74319b46ba77..d2882faf5644 100644
--- a/layout/html/forms/src/nsFileControlFrame.cpp
+++ b/layout/html/forms/src/nsFileControlFrame.cpp
@@ -249,8 +249,8 @@ nsFileControlFrame::MouseClick(nsIDOMEvent* aMouseEvent)
   nsComponentManager::CreateInstance(kCFileWidgetCID, nsnull, kIFileWidgetIID, (void**)&fileWidget);
   
   if (fileWidget) {
-    nsString titles[] = {"all files"};
-    nsString filters[] = {"*.*"};
+    nsString titles[1]; titles[0].AssignWithConversion("all files");
+    nsString filters[1]; filters[0].AssignWithConversion("*.*");
     fileWidget->SetFilterList(1, titles, filters);
 
     fileWidget->Create(parentWidget, title, eMode_load, nsnull, nsnull);
diff --git a/layout/html/forms/src/nsFormControlHelper.cpp b/layout/html/forms/src/nsFormControlHelper.cpp
index b28357ec572d..20e07a32a864 100644
--- a/layout/html/forms/src/nsFormControlHelper.cpp
+++ b/layout/html/forms/src/nsFormControlHelper.cpp
@@ -112,26 +112,20 @@ void nsFormControlHelper::ForceDrawFrame(nsIPresContext* aPresContext, nsIFrame
 void nsFormControlHelper::PlatformToDOMLineBreaks(nsString &aString)
 {
   // Windows linebreaks: Map CRLF to LF:
-  aString.ReplaceSubstring("\r\n", "\n");
+  aString.ReplaceSubstring(NS_ConvertASCIItoUCS2("\r\n"), NS_ConvertASCIItoUCS2("\n"));
 
   // Mac linebreaks: Map any remaining CR to LF:
-  aString.ReplaceSubstring("\r", "\n");
+  aString.ReplaceSubstring(NS_ConvertASCIItoUCS2("\r"), NS_ConvertASCIItoUCS2("\n"));
 }
 
 PRBool nsFormControlHelper::GetBool(const nsString& aValue)
 {
-  if (aValue.Equals(NS_STRING_TRUE))
-    return(PR_TRUE);
-  else
-    return (PR_FALSE);
+  return aValue.EqualsWithConversion(NS_STRING_TRUE);
 }
 
 void nsFormControlHelper::GetBoolString(const PRBool aValue, nsString& aResult)
 {
-  if (PR_TRUE == aValue)
-    aResult = NS_STRING_TRUE;
-  else
-    aResult = NS_STRING_FALSE;
+  aResult.AssignWithConversion( aValue ? NS_STRING_TRUE : NS_STRING_FALSE );
 }
 
 
@@ -172,7 +166,7 @@ nsresult nsFormControlHelper::GetFrameFontFM(nsIPresContext* aPresContext,
 nsresult
 nsFormControlHelper::GetWrapProperty(nsIContent * aContent, nsString &aOutValue)
 {
-  aOutValue = "";
+  aOutValue.SetLength(0);
   nsresult result = NS_CONTENT_ATTR_NOT_THERE;
   nsIHTMLContent* content = nsnull;
   aContent->QueryInterface(kIHTMLContentIID, (void**) &content);
@@ -198,16 +192,16 @@ nsFormControlHelper::GetWrapPropertyEnum(nsIContent * aContent, nsHTMLTextWrap&
 
   if (NS_CONTENT_ATTR_NOT_THERE != result) {
 
-    nsAutoString wrapHard(kTextControl_Wrap_Hard);
-    nsAutoString wrapPhysical(kTextControl_Wrap_Physical);
+    nsAutoString wrapHard; wrapHard.AssignWithConversion(kTextControl_Wrap_Hard);
+    nsAutoString wrapPhysical; wrapPhysical.AssignWithConversion(kTextControl_Wrap_Physical);
     if (wrap.EqualsIgnoreCase(wrapHard) ||
         wrap.EqualsIgnoreCase(wrapPhysical)) {
       aWrapProp = eHTMLTextWrap_Hard;
       return result;
     }
 
-    nsAutoString wrapSoft(kTextControl_Wrap_Soft);
-    nsAutoString wrapVirtual(kTextControl_Wrap_Virtual);
+    nsAutoString wrapSoft; wrapSoft.AssignWithConversion(kTextControl_Wrap_Soft);
+    nsAutoString wrapVirtual; wrapVirtual.AssignWithConversion(kTextControl_Wrap_Virtual);
     if (wrap.EqualsIgnoreCase(wrapSoft) ||
         wrap.EqualsIgnoreCase(wrapVirtual)) {
       aWrapProp = eHTMLTextWrap_Soft;
@@ -384,10 +378,10 @@ nsFormControlHelper::GetTextSize(nsIPresContext* aPresContext, nsIFormControlFra
   GetRepChars(aPresContext, char1, char2);
   int i;
   for (i = 0; i < aNumChars; i+=2) {
-    val += char1;  
+    val.AppendWithConversion(char1);  
   }
   for (i = 1; i < aNumChars; i+=2) {
-    val += char2;  
+    val.AppendWithConversion(char2);  
   }
   return GetTextSize(aPresContext, aFrame, val, aSize, aRendContext);
 }
diff --git a/layout/html/forms/src/nsGfxButtonControlFrame.cpp b/layout/html/forms/src/nsGfxButtonControlFrame.cpp
index 2c7f3aecf6c9..c760f8073d93 100644
--- a/layout/html/forms/src/nsGfxButtonControlFrame.cpp
+++ b/layout/html/forms/src/nsGfxButtonControlFrame.cpp
@@ -250,7 +250,7 @@ nsGfxButtonControlFrame::DoNavQuirksReflow(nsIPresContext*          aPresContext
     if (!textStyle->WhiteSpaceIsSignificant()) {
       value.CompressWhitespace();
       if (value.Length() == 0) {
-        value = "  ";
+        value.AssignWithConversion("  ");
       }
     }
 
@@ -384,7 +384,7 @@ nsGfxButtonControlFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
   if (!textStyle->WhiteSpaceIsSignificant()) {
     value.CompressWhitespace();
     if (value.Length() == 0) {
-      value = "  ";
+      value.AssignWithConversion("  ");
     }
   }
 
@@ -438,7 +438,7 @@ nsGfxButtonControlFrame::GetDefaultLabel(nsString& aString)
     rv = ButtonLocalize("Browse", aString);
   }
   else {
-    aString = "  ";
+    aString.AssignWithConversion("  ");
     rv = NS_OK;
   }
   return rv;
@@ -478,7 +478,7 @@ nsGfxButtonControlFrame::ButtonLocalize(char* aKey, nsString& oVal)
   // Determine default label from string bundle
   if (NS_SUCCEEDED(rv) && bundle && aKey) {
     nsXPIDLString valUni;
-    nsAutoString key(aKey);
+    nsAutoString key; key.AssignWithConversion(aKey);
     rv = bundle->GetStringFromName(key.GetUnicode(), getter_Copies(valUni));
     if (NS_SUCCEEDED(rv) && valUni) {
       oVal.Assign(valUni);
@@ -503,7 +503,7 @@ nsGfxButtonControlFrame::AttributeChanged(nsIPresContext* aPresContext,
     nsAutoString value;
     if (mTextContent && mContent) {
       if (NS_CONTENT_ATTR_HAS_VALUE != mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::value, value)) {
-        value = "";
+        value.SetLength(0);
       }
       rv = mTextContent->SetText(value.GetUnicode(), value.Length(), PR_TRUE);
     } else {
diff --git a/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp b/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp
index b1f766add59b..ba60057b8451 100644
--- a/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp
+++ b/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp
@@ -119,7 +119,7 @@ nsGfxCheckboxControlFrame::Init(nsIPresContext*  aPresContext,
 
   // give the attribute a default value so it's always present, if we're a tristate
   if ( IsTristateCheckbox() )
-    mContent->SetAttribute ( kNameSpaceID_None, GetTristateValueAtom(), "0", PR_FALSE );
+    mContent->SetAttribute ( kNameSpaceID_None, GetTristateValueAtom(), NS_ConvertASCIItoUCS2("0"), PR_FALSE );
   
   return NS_OK;
 }
@@ -494,7 +494,7 @@ nsGfxCheckboxControlFrame::GetNamesValues(PRInt32 aMaxNumValues, PRInt32& aNumVa
       result = PR_FALSE;
    } else {
      if (NS_CONTENT_ATTR_HAS_VALUE != valueResult) {
-       aValues[0] = "on";
+       aValues[0].AssignWithConversion("on");
      } else {
        aValues[0] = value;
      }
@@ -526,15 +526,15 @@ nsGfxCheckboxControlFrame::CheckStateToString ( CheckState inState, nsString& ou
 {
   switch ( inState ) {
     case eOn:
-      outStateAsString = NS_STRING_TRUE;
+      outStateAsString.AssignWithConversion(NS_STRING_TRUE);
 	  break;
 
     case eOff:
-      outStateAsString = NS_STRING_FALSE;
+      outStateAsString.AssignWithConversion(NS_STRING_FALSE);
       break;
  
     case eMixed:
-      outStateAsString = "2";
+      outStateAsString.AssignWithConversion("2");
       break;
   }
 } // CheckStateToString
@@ -549,9 +549,9 @@ nsGfxCheckboxControlFrame::CheckStateToString ( CheckState inState, nsString& ou
 nsGfxCheckboxControlFrame::CheckState 
 nsGfxCheckboxControlFrame::StringToCheckState ( const nsString & aStateAsString )
 {
-  if ( aStateAsString.Equals(NS_STRING_TRUE) )
+  if ( aStateAsString.EqualsWithConversion(NS_STRING_TRUE) )
     return eOn;
-  else if ( aStateAsString.Equals(NS_STRING_FALSE) )
+  else if ( aStateAsString.EqualsWithConversion(NS_STRING_FALSE) )
     return eOff;
 
   // not true and not false means mixed
@@ -614,7 +614,7 @@ NS_IMETHODIMP nsGfxCheckboxControlFrame::SaveState(nsIPresContext* aPresContext,
   // This string will hold a single item, whether or not we're checked.
   nsAutoString stateString;
   GetCheckboxControlFrameState(stateString);
-  (*aState)->SetStateProperty("checked", stateString);
+  (*aState)->SetStateProperty(NS_ConvertASCIItoUCS2("checked"), stateString);
 
   return NS_OK;
 }
@@ -628,7 +628,7 @@ NS_IMETHODIMP nsGfxCheckboxControlFrame::RestoreState(nsIPresContext* aPresConte
     mDidInit = PR_TRUE;
   }
   nsAutoString string;
-  aState->GetStateProperty("checked", string);
+  aState->GetStateProperty(NS_ConvertASCIItoUCS2("checked"), string);
   SetCheckboxControlFrameState(aPresContext, string);
   return NS_OK;
 }
diff --git a/layout/html/forms/src/nsGfxListControlFrame.cpp b/layout/html/forms/src/nsGfxListControlFrame.cpp
index 1764ec0efc50..0cad9cac7a3f 100644
--- a/layout/html/forms/src/nsGfxListControlFrame.cpp
+++ b/layout/html/forms/src/nsGfxListControlFrame.cpp
@@ -1343,10 +1343,10 @@ nsGfxListControlFrame::DisplaySelected(nsIContent* aContent)
    // The event state manager supports selected states. KMM
   
   if (PR_TRUE == mIsAllFramesHere) {
-    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, "", PR_TRUE);
+    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, nsAutoString(), PR_TRUE);
     //ForceRedraw();
   } else {
-    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, "", PR_FALSE);
+    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, nsAutoString(), PR_FALSE);
   }
 }
 
@@ -2229,7 +2229,7 @@ nsGfxListControlFrame::Reset(nsIPresContext* aPresContext)
   // Ok, so we were restored, now set the last known selections from the restore state.
   if (hasBeenRestored) {
     nsCOMPtr<nsISupports> supp;
-    mPresState->GetStatePropertyAsSupports("selecteditems", getter_AddRefs(supp));
+    mPresState->GetStatePropertyAsSupports(NS_ConvertASCIItoUCS2("selecteditems"), getter_AddRefs(supp));
 
     nsresult res = NS_ERROR_NULL_POINTER;
     if (!supp)
@@ -2408,7 +2408,7 @@ nsGfxListControlFrame::SetComboboxFrame(nsIFrame* aComboboxFrame)
 NS_IMETHODIMP 
 nsGfxListControlFrame::GetSelectedItem(nsString & aStr)
 {
-  aStr = "";
+  aStr.SetLength(0);
   nsresult rv = NS_ERROR_FAILURE; 
   nsCOMPtr<nsIDOMHTMLCollection> options = getter_AddRefs(GetOptions(mContent));
 
@@ -2898,7 +2898,7 @@ nsGfxListControlFrame::GetProperty(nsIAtom* aName, nsString& aValue)
     if ((kNothingSelected == selectedIndex) && (mComboboxFrame)) {
       selectedIndex = 0;
     }
-    aValue.Append(selectedIndex, 10);
+    aValue.AppendInt(selectedIndex, 10);
   }
 
   return NS_OK;
@@ -3855,7 +3855,7 @@ nsGfxListControlFrame::SaveStateInternal(nsIPresContext* aPresContext, nsIPresSt
   }
   
   NS_NewPresState(aState);
-  (*aState)->SetStatePropertyAsSupports("selecteditems", value);
+  (*aState)->SetStatePropertyAsSupports(NS_ConvertASCIItoUCS2("selecteditems"), value);
   return res;
 }
 
diff --git a/layout/html/forms/src/nsGfxRadioControlFrame.cpp b/layout/html/forms/src/nsGfxRadioControlFrame.cpp
index 3421411658c0..f121b4d4c4db 100644
--- a/layout/html/forms/src/nsGfxRadioControlFrame.cpp
+++ b/layout/html/forms/src/nsGfxRadioControlFrame.cpp
@@ -125,7 +125,7 @@ nsGfxRadioControlFrame::SetAdditionalStyleContext(PRInt32 aIndex,
 NS_IMETHODIMP nsGfxRadioControlFrame::SetProperty(nsIPresContext* aPresContext, nsIAtom* aName, const nsString& aValue)
 {
   if (nsHTMLAtoms::checked == aName) {
-    PRBool state = (aValue.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
+    PRBool state = (aValue.EqualsWithConversion(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
 
     // if there is no form than the radiobtn is an orphan
@@ -185,9 +185,9 @@ nsGfxRadioControlFrame::SetChecked(nsIPresContext* aPresContext, PRBool aValue,
 {
   if (aSetInitialValue) {
     if (aValue) {
-      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, nsAutoString("1"), PR_FALSE); // XXX should be "empty" value
+      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, NS_ConvertASCIItoUCS2("1"), PR_FALSE); // XXX should be "empty" value
     } else {
-      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, nsAutoString("0"), PR_FALSE);
+      mContent->SetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::checked, NS_ConvertASCIItoUCS2("0"), PR_FALSE);
     }
   }
 
@@ -226,7 +226,7 @@ nsGfxRadioControlFrame::GetNamesValues(PRInt32 aMaxNumValues, PRInt32& aNumValue
   if (NS_CONTENT_ATTR_HAS_VALUE == result) {
     aValues[0] = value;
   } else {
-    aValues[0] = "on";
+    aValues[0].AssignWithConversion("on");
   }
   aNames[0]  = name;
   aNumValues = 1;
@@ -345,7 +345,7 @@ nsGfxRadioControlFrame::SaveState(nsIPresContext* aPresContext, nsIPresState** a
   // This string will hold a single item, whether or not we're checked.
   nsAutoString stateString;
 	nsFormControlHelper::GetBoolString(GetRadioState(), stateString);
-  (*aState)->SetStateProperty("checked", stateString);
+  (*aState)->SetStateProperty(NS_ConvertASCIItoUCS2("checked"), stateString);
 
   return NS_OK;
 }
@@ -364,8 +364,8 @@ nsGfxRadioControlFrame::RestoreState(nsIPresContext* aPresContext, nsIPresState*
 
   mIsRestored = PR_TRUE;
   nsAutoString string;
-  aState->GetStateProperty("checked", string);
-  PRBool state = (string.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
+  aState->GetStateProperty(NS_ConvertASCIItoUCS2("checked"), string);
+  PRBool state = (string.EqualsWithConversion(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
   SetRadioState(aPresContext, state); // sets mChecked
   mRestoredChecked = mChecked;
diff --git a/layout/html/forms/src/nsGfxTextControlFrame.cpp b/layout/html/forms/src/nsGfxTextControlFrame.cpp
index 5bbe24dbd26c..87d434e1a347 100644
--- a/layout/html/forms/src/nsGfxTextControlFrame.cpp
+++ b/layout/html/forms/src/nsGfxTextControlFrame.cpp
@@ -955,7 +955,7 @@ NS_METHOD nsGfxTextControlFrame::HandleEvent(nsIPresContext* aPresContext,
     break;
     
     case NS_FORM_SELECTED:
-      return UpdateTextControlCommands(nsAutoString("select"));
+      return UpdateTextControlCommands(NS_ConvertASCIItoUCS2("select"));
       break;
   }
   return NS_OK;
@@ -1106,7 +1106,7 @@ nsGfxTextControlFrame::GetText(nsString* aText, PRBool aInitialValue)
           nsCOMPtr<nsIEditorIMESupport> imeSupport = do_QueryInterface(mEditor);
           if(imeSupport) 
               imeSupport->ForceCompositionEnd();
-          nsString format ("text/plain");
+          nsString format; format.AssignWithConversion("text/plain");
           mEditor->OutputToString(*aText, format, 0);
         }
         // we've never built our editor, so the content attribute is the value
@@ -1494,7 +1494,7 @@ nsGfxTextControlFrame::Paint(nsIPresContext* aPresContext,
 #endif
   if (NS_FRAME_PAINT_LAYER_FOREGROUND == aWhichLayer) 
   {
-    nsAutoString text(" ");
+    nsAutoString text; text.AssignWithConversion(" ");
     nsRect rect(0, 0, mRect.width, mRect.height);
     PaintTextControl(aPresContext, aRenderingContext, aDirtyRect, 
                      text, mStyleContext, rect);
@@ -1511,7 +1511,7 @@ nsGfxTextControlFrame::PaintTextControlBackground(nsIPresContext* aPresContext,
   // we paint our own border, but everything else is painted by the mDocshell
   if (NS_FRAME_PAINT_LAYER_FOREGROUND == aWhichLayer) 
   {
-    nsAutoString text(" ");
+    nsAutoString text; text.AssignWithConversion(" ");
     nsRect rect(0, 0, mRect.width, mRect.height);
     PaintTextControl(aPresContext, aRenderingContext, aDirtyRect, 
                      text, mStyleContext, rect);
@@ -1629,11 +1629,11 @@ nsGfxTextControlFrame::PaintTextControl(nsIPresContext* aPresContext,
 //XXX: this needs to be fixed for HTML output
 void nsGfxTextControlFrame::GetTextControlFrameState(nsString& aValue)
 {
-  aValue = "";  // initialize out param
+  aValue.SetLength(0);  // initialize out param
   
   if (mEditor && PR_TRUE==IsInitialized()) 
   {
-    nsString format ("text/plain");
+    nsString format; format.AssignWithConversion("text/plain");
     PRUint32 flags = 0;
 
     if (PR_TRUE==IsPlainTextControl()) {
@@ -1667,7 +1667,7 @@ void nsGfxTextControlFrame::SetTextControlFrameState(const nsString& aValue)
   if (mEditor && PR_TRUE==IsInitialized()) 
   {
     nsAutoString currentValue;
-    nsAutoString format ("text/plain");
+    nsAutoString format; format.AssignWithConversion("text/plain");
     nsresult result = mEditor->OutputToString(currentValue, format, 0);
     if (PR_TRUE==IsSingleLineTextControl()) {
       RemoveNewlines(currentValue); 
@@ -1678,7 +1678,7 @@ void nsGfxTextControlFrame::SetTextControlFrameState(const nsString& aValue)
       // so convert windows and mac platform linebreaks to \n:
       // Unfortunately aValue is declared const, so we have to copy
       // in order to do this substitution.
-      currentValue = aValue;
+      currentValue.Assign(aValue);
       nsFormControlHelper::PlatformToDOMLineBreaks(currentValue);
 
       nsCOMPtr<nsIDOMDocument>domDoc;
@@ -2552,7 +2552,7 @@ nsGfxTextControlFrame::Reflow(nsIPresContext* aPresContext,
           // get the text value, either from input element attribute or cached state
           nsAutoString value;
           if (mCachedState) {
-            value = *mCachedState;
+            value.Assign(*mCachedState);
 	        } 
           else 
           {
@@ -3301,7 +3301,7 @@ nsGfxTextControlFrame::InitializeTextControl(nsIPresShell *aPresShell, nsIDOMDoc
   // now that the style context is initialized, initialize the content
   nsAutoString value;
   if (mCachedState) {
-    value = *mCachedState;
+    value.Assign(*mCachedState);
     delete mCachedState;
     mCachedState = nsnull;
   } else {
@@ -3363,7 +3363,7 @@ nsGfxTextControlFrame::InitializeTextControl(nsIPresShell *aPresShell, nsIDOMDoc
     if (NS_FAILED(result)) { return result; }
     if (!selection) { return NS_ERROR_NULL_POINTER; }
     nsCOMPtr<nsIDOMNode>bodyNode;
-    nsAutoString bodyTag = "body";
+    nsAutoString bodyTag; bodyTag.AssignWithConversion("body");
     result = GetFirstNodeOfType(bodyTag, aDoc, getter_AddRefs(bodyNode));
     if (NS_SUCCEEDED(result) && bodyNode)
     {
@@ -3463,7 +3463,7 @@ nsresult nsGfxTextControlFrame::UpdateTextControlCommands(const nsString& aComma
   
   if (mEditor)
   {  
-    if (aCommand == nsAutoString("select"))   // optimize select updates
+    if (aCommand == NS_ConvertASCIItoUCS2("select"))   // optimize select updates
     {
       nsCOMPtr<nsIDOMSelection> domSelection;
       rv = mEditor->GetSelection(getter_AddRefs(domSelection));
@@ -3573,7 +3573,7 @@ nsGfxTextControlFrame::SaveState(nsIPresContext* aPresContext, nsIPresState** aS
            nsLinebreakConverter::eLinebreakPlatform, nsLinebreakConverter::eLinebreakContent);
   NS_ASSERTION(NS_SUCCEEDED(res), "Converting linebreaks failed!");  
   
-  (*aState)->SetStateProperty("value", theString);
+  (*aState)->SetStateProperty(NS_ConvertASCIItoUCS2("value"), theString);
   return res;
 }
 
@@ -3581,7 +3581,7 @@ NS_IMETHODIMP
 nsGfxTextControlFrame::RestoreState(nsIPresContext* aPresContext, nsIPresState* aState)
 {
   nsAutoString stateString;
-  aState->GetStateProperty("value", stateString);
+  aState->GetStateProperty(NS_ConvertASCIItoUCS2("value"), stateString);
   nsresult res = SetProperty(aPresContext, nsHTMLAtoms::value, stateString);
   return res;
 }
@@ -4419,7 +4419,7 @@ nsEnderEventListener::Focus(nsIDOMEvent* aEvent)
   nsGfxTextControlFrame *gfxFrame = mFrame.Reference();
 
   if (gfxFrame && mContent && mView) {
-    mTextValue = "";
+    mTextValue.SetLength(0);
     gfxFrame->GetText(&mTextValue, PR_FALSE);
   }
 
@@ -4594,7 +4594,7 @@ NS_IMETHODIMP nsEnderEventListener::DidDo(nsITransactionManager *aManager,
     if (undoCount == 1)
     {
       if (mFirstDoOfFirstUndo)
-        gfxFrame->UpdateTextControlCommands(nsAutoString("undo"));
+        gfxFrame->UpdateTextControlCommands(NS_ConvertASCIItoUCS2("undo"));
  
       mFirstDoOfFirstUndo = PR_FALSE;
     }
@@ -4621,7 +4621,7 @@ NS_IMETHODIMP nsEnderEventListener::DidUndo(nsITransactionManager *aManager,
     if (undoCount == 0)
       mFirstDoOfFirstUndo = PR_TRUE;    // reset the state for the next do
 
-    gfxFrame->UpdateTextControlCommands(nsAutoString("undo"));
+    gfxFrame->UpdateTextControlCommands(NS_ConvertASCIItoUCS2("undo"));
   }
   
   return NS_OK;
@@ -4640,7 +4640,7 @@ NS_IMETHODIMP nsEnderEventListener::DidRedo(nsITransactionManager *aManager,
   nsGfxTextControlFrame *gfxFrame = mFrame.Reference();
   if (gfxFrame)
   {
-    gfxFrame->UpdateTextControlCommands(nsAutoString("undo"));
+    gfxFrame->UpdateTextControlCommands(NS_ConvertASCIItoUCS2("undo"));
   }
 
   return NS_OK;
diff --git a/layout/html/forms/src/nsListControlFrame.cpp b/layout/html/forms/src/nsListControlFrame.cpp
index 1887624496a2..785e4b447af4 100644
--- a/layout/html/forms/src/nsListControlFrame.cpp
+++ b/layout/html/forms/src/nsListControlFrame.cpp
@@ -910,10 +910,10 @@ nsListControlFrame::DisplaySelected(nsIContent* aContent)
    // The event state manager supports selected states. KMM
   
   if (PR_TRUE == mIsAllFramesHere) {
-    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, "", PR_TRUE);
+    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, nsAutoString(), PR_TRUE);
     //ForceRedraw();
   } else {
-    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, "", PR_FALSE);
+    aContent->SetAttribute(kNameSpaceID_None, nsLayoutAtoms::optionSelectedPseudo, nsAutoString(), PR_FALSE);
   }
 }
 
@@ -1770,7 +1770,7 @@ nsListControlFrame::Reset(nsIPresContext* aPresContext)
   // Ok, so we were restored, now set the last known selections from the restore state.
   if (hasBeenRestored) {
     nsCOMPtr<nsISupports> supp;
-    mPresState->GetStatePropertyAsSupports("selecteditems", getter_AddRefs(supp));
+    mPresState->GetStatePropertyAsSupports(NS_ConvertASCIItoUCS2("selecteditems"), getter_AddRefs(supp));
 
     nsresult res = NS_ERROR_NULL_POINTER;
     if (!supp)
@@ -1949,7 +1949,7 @@ nsListControlFrame::SetComboboxFrame(nsIFrame* aComboboxFrame)
 NS_IMETHODIMP 
 nsListControlFrame::GetSelectedItem(nsString & aStr)
 {
-  aStr = "";
+  aStr.SetLength(0);
   nsresult rv = NS_ERROR_FAILURE; 
   nsCOMPtr<nsIDOMHTMLCollection> options = getter_AddRefs(GetOptions(mContent));
 
@@ -2429,7 +2429,7 @@ nsListControlFrame::GetProperty(nsIAtom* aName, nsString& aValue)
     if ((kNothingSelected == selectedIndex) && (mComboboxFrame)) {
       selectedIndex = 0;
     }
-    aValue.Append(selectedIndex, 10);
+    aValue.AppendInt(selectedIndex, 10);
   }
 
   return NS_OK;
@@ -3364,7 +3364,7 @@ nsListControlFrame::SaveStateInternal(nsIPresContext* aPresContext, nsIPresState
   }
   
   NS_NewPresState(aState);
-  (*aState)->SetStatePropertyAsSupports("selecteditems", value);
+  (*aState)->SetStatePropertyAsSupports(NS_ConvertASCIItoUCS2("selecteditems"), value);
   return res;
 }
 
diff --git a/layout/html/style/src/nsCSSFrameConstructor.cpp b/layout/html/style/src/nsCSSFrameConstructor.cpp
index 91c478d384b0..7cd8ab661154 100644
--- a/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -1342,7 +1342,7 @@ nsCSSFrameConstructor::CreateGeneratedContentFrame(nsIPresShell*        aPresShe
 
         nsCOMPtr<nsIDOMDocument> domdoc(do_QueryInterface(document));
         nsresult  result;
-        result = domdoc->CreateElement("SPAN",getter_AddRefs(containerElement));//is the literal the correct way?
+        result = domdoc->CreateElement(NS_ConvertASCIItoUCS2("SPAN"),getter_AddRefs(containerElement));//is the literal the correct way?
         if (NS_SUCCEEDED(result) && containerElement)
         {
           containerContent = do_QueryInterface(containerElement);
diff --git a/layout/xbl/src/nsXBLBinding.cpp b/layout/xbl/src/nsXBLBinding.cpp
index 96bb42dcfa48..4125155b9d52 100644
--- a/layout/xbl/src/nsXBLBinding.cpp
+++ b/layout/xbl/src/nsXBLBinding.cpp
@@ -495,7 +495,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
     // in the excludes list.
     nsAutoString excludes;
     content->GetAttribute(kNameSpaceID_None, kExcludesAtom, excludes);
-    if (!excludes.Equals("*")) {
+    if (!excludes.EqualsWithConversion("*")) {
       if (!excludes.IsEmpty()) {
         // Walk the children and ensure that all of them
         // are in the excludes array.
@@ -540,7 +540,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
       nsCOMPtr<nsIDOMAttr> attr(do_QueryInterface(attribute));
       nsAutoString name;
       attr->GetName(name);
-      if (!name.Equals("excludes")) {
+      if (!name.EqualsWithConversion("excludes")) {
         nsAutoString value;
         nsCOMPtr<nsIDOMElement> element(do_QueryInterface(mBoundElement));
         element->GetAttribute(name, value);
@@ -616,7 +616,7 @@ nsXBLBinding::InstallEventHandlers(nsIContent* aBoundElement)
             PRBool useCapture = PR_FALSE;
             nsAutoString capturer;
             child->GetAttribute(kNameSpaceID_None, kCapturerAtom, capturer);
-            if (capturer.Equals("true"))
+            if (capturer.EqualsWithConversion("true"))
               useCapture = PR_TRUE;
 
             // Add the event listener.
@@ -742,8 +742,9 @@ nsXBLBinding::InstallProperties(nsIContent* aBoundElement)
         // and then define it as a property.
         if (!body.IsEmpty()) {
           void* myFunc;
+          nsCAutoString cname; cname.AssignWithConversion(name.GetUnicode());
           rv = context->CompileFunction(mScriptObject,
-                                        name,
+                                        cname,
                                         argCount,
                                         (const char**)args,
                                         body, 
@@ -769,7 +770,7 @@ nsXBLBinding::InstallProperties(nsIContent* aBoundElement)
           void* setFunc = nsnull;
           uintN attrs = 0;
 
-          if (readOnly.Equals("true"))
+          if (readOnly.EqualsWithConversion("true"))
             attrs |= JSPROP_READONLY;
 
           if (!getter.IsEmpty()) {
@@ -1139,7 +1140,7 @@ nsXBLBinding::IsInExcludesList(nsIAtom* aTag, const nsString& aList)
   nsAutoString element;
   aTag->ToString(element);
 
-  if (aList.Equals("*"))
+  if (aList.EqualsWithConversion("*"))
       return PR_TRUE; // match _everything_!
 
   PRInt32 indx = aList.Find(element);
@@ -1185,7 +1186,7 @@ nsXBLBinding::ConstructAttributeTable(nsIContent* aElement)
       nsCOMPtr<nsIAtom> attribute;
 
       // Figure out if this token contains a :. 
-      nsAutoString attr(token);
+      nsAutoString attr; attr.AssignWithConversion(token);
       PRInt32 index = attr.Find(":", PR_TRUE);
       if (index != -1) {
         // This attribute maps to something different.
@@ -1281,21 +1282,21 @@ nsXBLBinding::GetEventHandlerIID(nsIAtom* aName, nsIID* aIID, PRBool* aFound)
 PRBool
 nsXBLBinding::IsMouseHandler(const nsString& aName)
 {
-  return ((aName.Equals("click")) || (aName.Equals("dblclick")) || (aName.Equals("mousedown")) ||
-          (aName.Equals("mouseover")) || (aName.Equals("mouseout")) || (aName.Equals("mouseup")));
+  return ((aName.EqualsWithConversion("click")) || (aName.EqualsWithConversion("dblclick")) || (aName.EqualsWithConversion("mousedown")) ||
+          (aName.EqualsWithConversion("mouseover")) || (aName.EqualsWithConversion("mouseout")) || (aName.EqualsWithConversion("mouseup")));
 }
 
 PRBool
 nsXBLBinding::IsKeyHandler(const nsString& aName)
 {
-  return ((aName.Equals("keypress")) || (aName.Equals("keydown")) || (aName.Equals("keyup")));
+  return ((aName.EqualsWithConversion("keypress")) || (aName.EqualsWithConversion("keydown")) || (aName.EqualsWithConversion("keyup")));
 }
 
 PRBool
 nsXBLBinding::IsXULHandler(const nsString& aName)
 {
-  return ((aName.Equals("create")) || (aName.Equals("destroy")) || (aName.Equals("broadcast")) ||
-          (aName.Equals("command")) || (aName.Equals("commandupdate")) || (aName.Equals("close")));
+  return ((aName.EqualsWithConversion("create")) || (aName.EqualsWithConversion("destroy")) || (aName.EqualsWithConversion("broadcast")) ||
+          (aName.EqualsWithConversion("command")) || (aName.EqualsWithConversion("commandupdate")) || (aName.EqualsWithConversion("close")));
 }
 
 NS_IMETHODIMP
@@ -1304,7 +1305,7 @@ nsXBLBinding::AddScriptEventListener(nsIContent* aElement, nsIAtom* aName, const
   nsAutoString val;
   aName->ToString(val);
   
-  nsAutoString eventStr("on");
+  nsAutoString eventStr; eventStr.AssignWithConversion("on");
   eventStr += val;
 
   nsCOMPtr<nsIAtom> eventName = getter_AddRefs(NS_NewAtom(eventStr));
diff --git a/layout/xbl/src/nsXBLEventHandler.cpp b/layout/xbl/src/nsXBLEventHandler.cpp
index 18224baab385..711ea222972f 100644
--- a/layout/xbl/src/nsXBLEventHandler.cpp
+++ b/layout/xbl/src/nsXBLEventHandler.cpp
@@ -58,7 +58,7 @@ nsXBLEventHandler::nsXBLEventHandler(nsIContent* aBoundElement, nsIContent* aHan
   NS_INIT_REFCNT();
   mBoundElement = aBoundElement;
   mHandlerElement = aHandlerElement;
-  mEventName = aEventName;
+  mEventName.Assign(aEventName);
   gRefCnt++;
   if (gRefCnt == 1) {
     kKeyCodeAtom = NS_NewAtom("keycode");
@@ -101,154 +101,154 @@ nsresult nsXBLEventHandler::HandleEvent(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::KeyUp(nsIDOMEvent* aKeyEvent)
 {
-  if (!mEventName.Equals("keyup"))
+  if (!mEventName.EqualsWithConversion("keyup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
   if (KeyEventMatched(keyEvent))
-    ExecuteHandler(nsAutoString("keyup"), aKeyEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("keyup"), aKeyEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::KeyDown(nsIDOMEvent* aKeyEvent)
 {
-  if (!mEventName.Equals("keydown"))
+  if (!mEventName.EqualsWithConversion("keydown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
   if (KeyEventMatched(keyEvent))
-    ExecuteHandler(nsAutoString("keydown"), aKeyEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("keydown"), aKeyEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::KeyPress(nsIDOMEvent* aKeyEvent)
 {
-  if (!mEventName.Equals("keypress"))
+  if (!mEventName.EqualsWithConversion("keypress"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
   if (KeyEventMatched(keyEvent))
-    ExecuteHandler(nsAutoString("keypress"), aKeyEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("keypress"), aKeyEvent);
   return NS_OK;
 }
    
 nsresult nsXBLEventHandler::MouseDown(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mousedown"))
+  if (!mEventName.EqualsWithConversion("mousedown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mousedown"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mousedown"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseUp(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mouseup"))
+  if (!mEventName.EqualsWithConversion("mouseup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mouseup"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mouseup"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseClick(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("click"))
+  if (!mEventName.EqualsWithConversion("click"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("click"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("click"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseDblClick(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("dblclick"))
+  if (!mEventName.EqualsWithConversion("dblclick"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("dblclick"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("dblclick"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseOver(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mouseover"))
+  if (!mEventName.EqualsWithConversion("mouseover"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mouseover"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mouseover"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::MouseOut(nsIDOMEvent* aMouseEvent)
 {
-  if (!mEventName.Equals("mouseout"))
+  if (!mEventName.EqualsWithConversion("mouseout"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
   if (MouseEventMatched(mouseEvent))
-    ExecuteHandler(nsAutoString("mouseout"), aMouseEvent);
+    ExecuteHandler(NS_ConvertASCIItoUCS2("mouseout"), aMouseEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Action(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("command"))
+  if (!mEventName.EqualsWithConversion("command"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("command"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("command"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Create(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("create"))
+  if (!mEventName.EqualsWithConversion("create"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("create"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("create"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Close(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("close"))
+  if (!mEventName.EqualsWithConversion("close"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("close"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("close"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Broadcast(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("broadcast"))
+  if (!mEventName.EqualsWithConversion("broadcast"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("broadcast"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("broadcast"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::CommandUpdate(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("commandupdate"))
+  if (!mEventName.EqualsWithConversion("commandupdate"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("commandupdate"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("commandupdate"), aEvent);
   return NS_OK;
 }
 
 nsresult nsXBLEventHandler::Destroy(nsIDOMEvent* aEvent)
 {
-  if (!mEventName.Equals("destroy"))
+  if (!mEventName.EqualsWithConversion("destroy"))
     return NS_OK;
 
-  ExecuteHandler(nsAutoString("destroy"), aEvent);
+  ExecuteHandler(NS_ConvertASCIItoUCS2("destroy"), aEvent);
   return NS_OK;
 }
 
@@ -257,8 +257,8 @@ nsresult nsXBLEventHandler::Destroy(nsIDOMEvent* aEvent)
 PRBool 
 nsXBLEventHandler::KeyEventMatched(nsIDOMKeyEvent* aKeyEvent)
 {
-  nsAutoString trueString = "true";
-  nsAutoString falseString = "false";
+  nsAutoString trueString; trueString.AssignWithConversion("true");
+  nsAutoString falseString; falseString.AssignWithConversion("false");
 
   // Get the keycode and charcode of the key event.
   PRUint32 keyCode, charCode;
@@ -272,12 +272,12 @@ nsXBLEventHandler::KeyEventMatched(nsIDOMKeyEvent* aKeyEvent)
   if (!key.IsEmpty())
     keyMatched = IsMatchingCharCode(charCode, key);
   
-  key = "";
+  key.SetLength(0);
   mHandlerElement->GetAttribute(kNameSpaceID_None, kKeyCodeAtom, key);
   if (!key.IsEmpty())
     keyMatched = IsMatchingKeyCode(keyCode, key);
   
-  key = "";
+  key.SetLength(0);
   mHandlerElement->GetAttribute(kNameSpaceID_None, kCharCodeAtom, key);
   if (!key.IsEmpty())
     keyMatched = IsMatchingCharCode(charCode, key);
@@ -374,8 +374,8 @@ nsXBLEventHandler::KeyEventMatched(nsIDOMKeyEvent* aKeyEvent)
 PRBool 
 nsXBLEventHandler::MouseEventMatched(nsIDOMUIEvent* aMouseEvent)
 {
-  nsAutoString trueString = "true";
-  nsAutoString falseString = "false";
+  nsAutoString trueString; trueString.AssignWithConversion("true");
+  nsAutoString falseString; falseString.AssignWithConversion("false");
 
   // XXX Check for button and modifier keys.
 
@@ -408,7 +408,7 @@ nsXBLEventHandler::ExecuteHandler(const nsString& aEventName, nsIDOMEvent* aEven
 
   // Look for a compiled handler on the element. 
   // Should be compiled and bound with "on" in front of the name.
-  nsAutoString onEvent = "onxbl";
+  nsAutoString onEvent; onEvent.AssignWithConversion("onxbl");
   onEvent += aEventName;
   nsCOMPtr<nsIAtom> onEventAtom = getter_AddRefs(NS_NewAtom(onEvent));
 
@@ -1066,7 +1066,7 @@ nsXBLEventHandler::IsMatchingCharCode(const PRUint32 aChar, const nsString& aKey
   char tempChar[2];
   tempChar[0] = aChar;
   tempChar[1] = 0;
-  nsAutoString tempChar2 = tempChar;
+  nsAutoString tempChar2; tempChar2.AssignWithConversion(tempChar);
   
   return tempChar2.EqualsIgnoreCase(aKeyName);
 }
diff --git a/layout/xbl/src/nsXBLService.cpp b/layout/xbl/src/nsXBLService.cpp
index c9d674c3faa9..2e3a0b7a3762 100644
--- a/layout/xbl/src/nsXBLService.cpp
+++ b/layout/xbl/src/nsXBLService.cpp
@@ -225,7 +225,7 @@ nsXBLService::nsXBLService(void)
     static const char kXBLNameSpaceURI[]
         = "http://www.mozilla.org/xbl";
 
-    rv = gNameSpaceManager->RegisterNameSpace(kXBLNameSpaceURI, kNameSpaceID_XBL);
+    rv = gNameSpaceManager->RegisterNameSpace(NS_ConvertASCIItoUCS2(kXBLNameSpaceURI), kNameSpaceID_XBL);
     NS_ASSERTION(NS_SUCCEEDED(rv), "unable to register XBL namespace");
     if (NS_FAILED(rv)) return;
 
@@ -272,7 +272,7 @@ nsXBLService::LoadBindings(nsIContent* aContent, const nsString& aURL)
 
   if (!binding) {
     nsCAutoString str = "Failed to locate XBL binding.  The invalid binding name is: ";
-    str += aURL;
+    str.AppendWithConversion(aURL);
     NS_ERROR(str);
     return NS_ERROR_FAILURE;
   }
@@ -403,7 +403,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
   if (!root)
     return NS_ERROR_FAILURE;
 
-  nsAutoString bindingName(ref);
+  nsAutoString bindingName; bindingName.AssignWithConversion( NS_STATIC_CAST(const char*, ref) );
 
   PRInt32 count;
   root->ChildCount(count);
diff --git a/layout/xml/content/src/nsXMLCDATASection.cpp b/layout/xml/content/src/nsXMLCDATASection.cpp
index 7cf0436274cb..b70b0edb103c 100644
--- a/layout/xml/content/src/nsXMLCDATASection.cpp
+++ b/layout/xml/content/src/nsXMLCDATASection.cpp
@@ -137,7 +137,7 @@ nsXMLCDATASection::GetTag(nsIAtom*& aResult) const
 NS_IMETHODIMP
 nsXMLCDATASection::GetNodeName(nsString& aNodeName)
 {
-  aNodeName.Assign("#cdata-section");
+  aNodeName.AssignWithConversion("#cdata-section");
   return NS_OK;
 }
 
diff --git a/layout/xml/content/src/nsXMLElement.cpp b/layout/xml/content/src/nsXMLElement.cpp
index 3e7eee011a46..ccad01016723 100644
--- a/layout/xml/content/src/nsXMLElement.cpp
+++ b/layout/xml/content/src/nsXMLElement.cpp
@@ -212,7 +212,7 @@ nsXMLElement::SetAttribute(PRInt32 aNameSpaceID, nsIAtom* aName,
   // to create an atom.
   if ((kNameSpaceID_XLink == aNameSpaceID) &&
       (kTypeAtom == aName)) { 
-    if (aValue.Equals(kSimpleAtom, PR_FALSE)) {
+    if (aValue.EqualsAtom(kSimpleAtom, PR_FALSE)) {
       // NOTE: This really is a link according to the XLink spec,
       //       we do not need to check other attributes. If there
       //       is no href attribute, then this link is simply
diff --git a/layout/xml/content/src/nsXMLEntity.cpp b/layout/xml/content/src/nsXMLEntity.cpp
index 25f0c548df55..66f2101893fd 100644
--- a/layout/xml/content/src/nsXMLEntity.cpp
+++ b/layout/xml/content/src/nsXMLEntity.cpp
@@ -266,19 +266,19 @@ nsXMLEntity::List(FILE* out, PRInt32 aIndent) const
 
   nsAutoString tmp(mName);
   if (mPublicId.Length()) {
-    tmp.Append(" PUBLIC \"");
+    tmp.AppendWithConversion(" PUBLIC \"");
     tmp.Append(mPublicId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   if (mSystemId.Length()) {
-    tmp.Append(" SYSTEM \"");
+    tmp.AppendWithConversion(" SYSTEM \"");
     tmp.Append(mSystemId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   if (mNotationName.Length()) {
-    tmp.Append(" NDATA ");
+    tmp.AppendWithConversion(" NDATA ");
     tmp.Append(mNotationName);
   }
 
diff --git a/layout/xml/content/src/nsXMLNotation.cpp b/layout/xml/content/src/nsXMLNotation.cpp
index 3edd362596ec..c9548d45a4dc 100644
--- a/layout/xml/content/src/nsXMLNotation.cpp
+++ b/layout/xml/content/src/nsXMLNotation.cpp
@@ -254,15 +254,15 @@ nsXMLNotation::List(FILE* out, PRInt32 aIndent) const
 
   nsAutoString tmp(mName);
   if (mPublicId.Length()) {
-    tmp.Append(" PUBLIC \"");
+    tmp.AppendWithConversion(" PUBLIC \"");
     tmp.Append(mPublicId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   if (mSystemId.Length()) {
-    tmp.Append(" SYSTEM \"");
+    tmp.AppendWithConversion(" SYSTEM \"");
     tmp.Append(mSystemId);
-    tmp.Append("\"");
+    tmp.AppendWithConversion("\"");
   }
 
   fputs(tmp, out);
diff --git a/layout/xul/base/src/nsBoxFrame.cpp b/layout/xul/base/src/nsBoxFrame.cpp
index 4aea7aa482f1..a05014590197 100644
--- a/layout/xul/base/src/nsBoxFrame.cpp
+++ b/layout/xul/base/src/nsBoxFrame.cpp
@@ -1387,9 +1387,9 @@ nsBoxFrame::GetFrameName(nsString& aResult) const
     if (content)
        content->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::id, id);
 
-    aResult = "Box[id=";
+    aResult.AssignWithConversion("Box[id=");
     aResult.Append(id);
-    aResult.Append("]");
+    aResult.AppendWithConversion("]");
     return NS_OK;
 }
 
@@ -1985,9 +1985,9 @@ nsBoxFrameInner::DisplayDebugInfoFor(nsIBox* aBox,
                         childFrame->GetContent(getter_AddRefs(content));
 
                         if (content) {
-                            id = "";
-                            kClass = "";
-                            tagString = "";
+                            id.SetLength(0);
+                            kClass.SetLength(0);
+                            tagString.SetLength(0);
 
                             content->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::id, id);
                             id.ToCString(idValue,100);
diff --git a/layout/xul/base/src/nsColorPickerFrame.cpp b/layout/xul/base/src/nsColorPickerFrame.cpp
index 3e0a9d069dfc..bd33ce291a30 100644
--- a/layout/xul/base/src/nsColorPickerFrame.cpp
+++ b/layout/xul/base/src/nsColorPickerFrame.cpp
@@ -83,7 +83,7 @@ nsColorPickerFrame::Init(nsIPresContext*  aPresContext,
   nsAutoString type;
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::type, type);
 
-  if (type.EqualsIgnoreCase("swatch") || type.Equals(""))
+  if (type.EqualsIgnoreCase("swatch") || type.IsEmpty())
   {
     mColorPicker = new nsStdColorPicker();
     mColorPicker->Init(mContent);
@@ -126,9 +126,9 @@ nsColorPickerFrame::HandleMouseDownEvent(nsIPresContext* aPresContext,
   nsresult rv = mColorPicker->GetColor(x, y, &color);
 
   if (NS_FAILED(rv))
-    node->RemoveAttribute("color");
+    node->RemoveAttribute(NS_ConvertASCIItoUCS2("color"));
   else
-    node->SetAttribute("color", color);
+    node->SetAttribute(NS_ConvertASCIItoUCS2("color"), NS_ConvertASCIItoUCS2(color));
 
   return NS_OK;
 }
diff --git a/layout/xul/base/src/nsDeckFrame.h b/layout/xul/base/src/nsDeckFrame.h
index 0b1d6005ad31..18162636b1c9 100644
--- a/layout/xul/base/src/nsDeckFrame.h
+++ b/layout/xul/base/src/nsDeckFrame.h
@@ -63,7 +63,7 @@ public:
 #ifdef NS_DEBUG
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "Deck";
+      aResult.AssignWithConversion("Deck");
       return NS_OK;
   }
 #endif
diff --git a/layout/xul/base/src/nsGrippyFrame.cpp b/layout/xul/base/src/nsGrippyFrame.cpp
index 7b3823e0b5e6..b90ca75ccfaf 100644
--- a/layout/xul/base/src/nsGrippyFrame.cpp
+++ b/layout/xul/base/src/nsGrippyFrame.cpp
@@ -87,12 +87,12 @@ nsGrippyFrame::MouseClicked(nsIPresContext* aPresContext)
     nsCOMPtr<nsIContent> content;
     splitter->GetContent(getter_AddRefs(content));
  
-	nsString a = "collapsed";
+	nsString a; a.AssignWithConversion("collapsed");
 	nsString value;
     if (NS_CONTENT_ATTR_HAS_VALUE == content->GetAttribute(kNameSpaceID_None, nsXULAtoms::state, value))
     {
-     if (value.Equals("collapsed"))
-       a = "open";
+     if (value.EqualsWithConversion("collapsed"))
+       a.AssignWithConversion("open");
     }
 
     content->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, a, PR_TRUE);
@@ -238,6 +238,6 @@ nsGrippyFrame::GetChildAt(nsIPresContext* aPresContext, nsIFrame* parent, PRInt3
 NS_IMETHODIMP
 nsGrippyFrame::GetFrameName(nsString& aResult) const
 {
-  aResult = "Grippy";
+  aResult.AssignWithConversion("Grippy");
   return NS_OK;
 }
diff --git a/layout/xul/base/src/nsImageBoxFrame.cpp b/layout/xul/base/src/nsImageBoxFrame.cpp
index bace61922ee8..44da88607990 100644
--- a/layout/xul/base/src/nsImageBoxFrame.cpp
+++ b/layout/xul/base/src/nsImageBoxFrame.cpp
@@ -196,7 +196,7 @@ nsImageBoxFrame::Init(nsIPresContext*  aPresContext,
   // that UpdateAttributes doesn't double start an image load.
   nsAutoString src;
   GetImageSource(src);
-  if (!src.Equals("")) {
+  if (!src.IsEmpty()) {
     mHasImage = PR_TRUE;
   }
   mImageLoader.Init(this, UpdateImageFrame, nsnull, baseURL, src);
@@ -215,7 +215,7 @@ nsImageBoxFrame::GetImageSource(nsString& aResult)
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::src, aResult);
 
   // if the new image is empty
-  if (aResult.Equals("")) {
+  if (aResult.IsEmpty()) {
     // get the list-style-image
     const nsStyleList* myList =
       (const nsStyleList*)mStyleContext->GetStyleData(eStyleStruct_List);
@@ -244,7 +244,7 @@ nsImageBoxFrame::UpdateImage(nsIPresContext*  aPresContext, PRBool& aResize)
 
   // see if the source changed
   // get the old image src
-  nsAutoString oldSrc ="";
+  nsAutoString oldSrc;
   mImageLoader.GetURLSpec(oldSrc);
 
   // get the new image src
@@ -254,7 +254,7 @@ nsImageBoxFrame::UpdateImage(nsIPresContext*  aPresContext, PRBool& aResize)
    // see if the images are different
   if (!oldSrc.Equals(src)) {      
 
-        if (!src.Equals("")) {
+        if (!src.IsEmpty()) {
           mSizeFrozen = PR_FALSE;
           mHasImage = PR_TRUE;
         } else {
@@ -442,6 +442,6 @@ nsImageBoxFrame::CacheImageSize(nsBoxLayoutState& aState)
 NS_IMETHODIMP
 nsImageBoxFrame::GetFrameName(nsString& aResult) const
 {
-  aResult = "ImageBox";
+  aResult.AssignWithConversion("ImageBox");
   return NS_OK;
 }
diff --git a/layout/xul/base/src/nsLeafBoxFrame.cpp b/layout/xul/base/src/nsLeafBoxFrame.cpp
index 624945d85802..f110bc45d763 100644
--- a/layout/xul/base/src/nsLeafBoxFrame.cpp
+++ b/layout/xul/base/src/nsLeafBoxFrame.cpp
@@ -211,7 +211,7 @@ nsLeafBoxFrame::Reflow(nsIPresContext*   aPresContext,
 NS_IMETHODIMP
 nsLeafBoxFrame::GetFrameName(nsString& aResult) const
 {
-  aResult = "LeafBox";
+  aResult.AssignWithConversion("LeafBox");
   return NS_OK;
 }
 
diff --git a/layout/xul/base/src/nsMenuBarFrame.cpp b/layout/xul/base/src/nsMenuBarFrame.cpp
index f52c7bb25b66..38232150a610 100644
--- a/layout/xul/base/src/nsMenuBarFrame.cpp
+++ b/layout/xul/base/src/nsMenuBarFrame.cpp
@@ -125,12 +125,12 @@ nsMenuBarFrame::Init(nsIPresContext*  aPresContext,
   // Also hook up the listener to the window listening for focus events. This is so we can keep proper
   // state as the user alt-tabs through processes.
   
-  target->AddEventListener("keypress", (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE); 
-  target->AddEventListener("keydown", (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);  
-  target->AddEventListener("keyup", (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);   
+  target->AddEventListener(NS_ConvertASCIItoUCS2("keypress"), (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE); 
+  target->AddEventListener(NS_ConvertASCIItoUCS2("keydown"), (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);  
+  target->AddEventListener(NS_ConvertASCIItoUCS2("keyup"), (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);   
 
-  target->AddEventListener("mousedown", (nsIDOMMouseListener*)mMenuBarListener, PR_FALSE);   
-  target->AddEventListener("blur", (nsIDOMFocusListener*)mMenuBarListener, PR_TRUE);   
+  target->AddEventListener(NS_ConvertASCIItoUCS2("mousedown"), (nsIDOMMouseListener*)mMenuBarListener, PR_FALSE);   
+  target->AddEventListener(NS_ConvertASCIItoUCS2("blur"), (nsIDOMFocusListener*)mMenuBarListener, PR_TRUE);   
 
   return rv;
 }
@@ -157,9 +157,9 @@ nsMenuBarFrame::SetActive(PRBool aActiveFlag)
     InstallKeyboardNavigator();
   }
   else if (mKeyboardNavigator) {
-    mTarget->RemoveEventListener("keypress", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
-    mTarget->RemoveEventListener("keydown", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
-    mTarget->RemoveEventListener("keyup", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+    mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keypress"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+    mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keydown"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+    mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keyup"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
   
     NS_IF_RELEASE(mKeyboardNavigator);
   }
@@ -220,7 +220,7 @@ nsMenuBarFrame::FindMenuWithShortcut(PRUint32 aLetter)
     // See if it's a menu item.
     if (IsValidItem(current)) {
       // Get the shortcut attribute.
-      nsString shortcutKey = "";
+      nsString shortcutKey;
       current->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey, shortcutKey);
       shortcutKey.ToUpperCase();
       if (shortcutKey.Length() > 0) {
@@ -228,7 +228,7 @@ nsMenuBarFrame::FindMenuWithShortcut(PRUint32 aLetter)
         char tempChar[2];
         tempChar[0] = aLetter;
         tempChar[1] = 0;
-        nsAutoString tempChar2 = tempChar;
+        nsAutoString tempChar2; tempChar2.AssignWithConversion(tempChar);
   
         if (shortcutKey.EqualsIgnoreCase(tempChar2)) {
           // We match!
@@ -608,9 +608,9 @@ nsMenuBarFrame::InstallKeyboardNavigator()
   mKeyboardNavigator = new nsMenuListener(this);
   NS_IF_ADDREF(mKeyboardNavigator);
 
-  mTarget->AddEventListener("keypress", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE); 
-  mTarget->AddEventListener("keydown", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);  
-  mTarget->AddEventListener("keyup", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);   
+  mTarget->AddEventListener(NS_ConvertASCIItoUCS2("keypress"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE); 
+  mTarget->AddEventListener(NS_ConvertASCIItoUCS2("keydown"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);  
+  mTarget->AddEventListener(NS_ConvertASCIItoUCS2("keyup"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);   
   
   return NS_OK;
 }
@@ -621,9 +621,9 @@ nsMenuBarFrame::RemoveKeyboardNavigator()
   if (!mKeyboardNavigator || mIsActive)
     return NS_OK;
 
-  mTarget->RemoveEventListener("keypress", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
-  mTarget->RemoveEventListener("keydown", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
-  mTarget->RemoveEventListener("keyup", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keypress"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keydown"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keyup"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
   
   NS_IF_RELEASE(mKeyboardNavigator);
 
@@ -648,9 +648,9 @@ nsMenuBarFrame::IsValidItem(nsIContent* aContent)
 PRBool 
 nsMenuBarFrame::IsDisabled(nsIContent* aContent)
 {
-  nsString disabled = "";
+  nsString disabled;
   aContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, disabled);
-  if (disabled.Equals("true"))
+  if (disabled.EqualsWithConversion("true"))
     return PR_TRUE;
   return PR_FALSE;
 }
@@ -658,12 +658,12 @@ nsMenuBarFrame::IsDisabled(nsIContent* aContent)
 NS_IMETHODIMP
 nsMenuBarFrame::Destroy(nsIPresContext* aPresContext)
 {
-  mTarget->RemoveEventListener("keypress", (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE); 
-  mTarget->RemoveEventListener("keydown", (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);  
-  mTarget->RemoveEventListener("keyup", (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keypress"), (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE); 
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keydown"), (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);  
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keyup"), (nsIDOMKeyListener*)mMenuBarListener, PR_FALSE);
 
-  mTarget->RemoveEventListener("mousedown", (nsIDOMMouseListener*)mMenuBarListener, PR_FALSE);
-  mTarget->RemoveEventListener("blur", (nsIDOMFocusListener*)mMenuBarListener, PR_TRUE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("mousedown"), (nsIDOMMouseListener*)mMenuBarListener, PR_FALSE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("blur"), (nsIDOMFocusListener*)mMenuBarListener, PR_TRUE);
 
   NS_IF_RELEASE(mMenuBarListener);
 
diff --git a/layout/xul/base/src/nsMenuBarFrame.h b/layout/xul/base/src/nsMenuBarFrame.h
index 24543187e019..3a69d668a210 100644
--- a/layout/xul/base/src/nsMenuBarFrame.h
+++ b/layout/xul/base/src/nsMenuBarFrame.h
@@ -110,7 +110,7 @@ public:
 
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "MenuBar";
+      aResult.AssignWithConversion("MenuBar");
       return NS_OK;
   }
 
diff --git a/layout/xul/base/src/nsMenuFrame.cpp b/layout/xul/base/src/nsMenuFrame.cpp
index 46c943372e3a..dd8b3da7aceb 100644
--- a/layout/xul/base/src/nsMenuFrame.cpp
+++ b/layout/xul/base/src/nsMenuFrame.cpp
@@ -119,8 +119,7 @@ nsMenuFrame::nsMenuFrame(nsIPresShell* aShell):nsBoxFrame(aShell),
     mChecked(PR_FALSE),
     mType(eMenuType_Normal),
     mMenuParent(nsnull),
-    mPresContext(nsnull),
-    mGroupName("")
+    mPresContext(nsnull)
 {
 
 } // cntr
@@ -237,7 +236,7 @@ nsMenuFrame::GetFrameForPoint(nsIPresContext* aPresContext,
     // This allows selective overriding for subcontent.
     nsAutoString value;
     content->GetAttribute(kNameSpaceID_None, nsXULAtoms::allowevents, value);
-    if (value.Equals("true"))
+    if (value.EqualsWithConversion("true"))
       return result;
   }
   const nsStyleDisplay* disp = (const nsStyleDisplay*)
@@ -302,7 +301,7 @@ nsMenuFrame::HandleEvent(nsIPresContext* aPresContext,
                              PR_TRUE);
       }
       else {
-        mContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::checked, nsAutoString("true"),
+        mContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::checked, NS_ConvertASCIItoUCS2("true"),
                              PR_TRUE);
       }
         
@@ -391,7 +390,7 @@ nsMenuFrame::SelectMenu(PRBool aActivateFlag)
 {
   if (aActivateFlag) {
     // Highlight the menu.
-    mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, "true", PR_TRUE);
+    mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, NS_ConvertASCIItoUCS2("true"), PR_TRUE);
   }
   else {
     // Unhighlight the menu.
@@ -432,7 +431,7 @@ nsMenuFrame::MarkAsGenerated()
     nsAutoString genVal;
     child->GetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, genVal);
     if (genVal.IsEmpty())
-      child->SetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, "true", PR_TRUE);
+      child->SetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, NS_ConvertASCIItoUCS2("true"), PR_TRUE);
   }
 
   return NS_OK;
@@ -452,7 +451,7 @@ nsMenuFrame::ActivateMenu(PRBool aActivateFlag)
     // We wait until the last possible moment to show to avoid flashing, but we can just go
     // ahead and hide it here if we're told to (no additional stages necessary).
     if (aActivateFlag)
-      child->SetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, "true", PR_TRUE);
+      child->SetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, NS_ConvertASCIItoUCS2("true"), PR_TRUE);
     else {
       child->UnsetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, PR_TRUE);
       child->UnsetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, PR_TRUE);
@@ -473,7 +472,7 @@ nsMenuFrame::AttributeChanged(nsIPresContext* aPresContext,
 
   if (aAttribute == nsXULAtoms::open) {
     aChild->GetAttribute(kNameSpaceID_None, aAttribute, value);
-    if (value.Equals("true"))
+    if (value.EqualsWithConversion("true"))
       OpenMenuInternal(PR_TRUE);
     else
       OpenMenuInternal(PR_FALSE);
@@ -495,9 +494,9 @@ nsMenuFrame::OpenMenu(PRBool aActivateFlag)
     // Mark it as generated, which ensures a frame gets built.
     MarkAsGenerated();
 
-    domElement->SetAttribute("open", "true");
+    domElement->SetAttribute(NS_ConvertASCIItoUCS2("open"), NS_ConvertASCIItoUCS2("true"));
   }
-  else domElement->RemoveAttribute("open");
+  else domElement->RemoveAttribute(NS_ConvertASCIItoUCS2("open"));
 
   return NS_OK;
 }
@@ -578,15 +577,15 @@ nsMenuFrame::OpenMenuInternal(PRBool aActivateFlag)
       
       if (onMenuBar) {
         if (popupAnchor.IsEmpty())
-          popupAnchor = "bottomleft";
+          popupAnchor.AssignWithConversion("bottomleft");
         if (popupAlign.IsEmpty())
-          popupAlign = "topleft";
+          popupAlign.AssignWithConversion("topleft");
       }
       else {
         if (popupAnchor.IsEmpty())
-          popupAnchor = "topright";
+          popupAnchor.AssignWithConversion("topright");
         if (popupAlign.IsEmpty())
-          popupAlign = "topleft";
+          popupAlign.AssignWithConversion("topleft");
       }
 
       menuPopup->SyncViewWithFrame(mPresContext, popupAnchor, popupAlign, this, -1, -1);
@@ -887,15 +886,15 @@ nsMenuFrame::LayoutFinished(nsBoxLayoutState& aState)
 
     if (onMenuBar) {
       if (popupAnchor.IsEmpty())
-          popupAnchor = "bottomleft";
+          popupAnchor.AssignWithConversion("bottomleft");
       if (popupAlign.IsEmpty())
-          popupAlign = "topleft";
+          popupAlign.AssignWithConversion("topleft");
     }
     else {
       if (popupAnchor.IsEmpty())
-        popupAnchor = "topright";
+        popupAnchor.AssignWithConversion("topright");
       if (popupAlign.IsEmpty())
-        popupAlign = "topleft";
+        popupAlign.AssignWithConversion("topleft");
     }
 
     nsIPresContext* presContext = aState.GetPresContext();
@@ -992,9 +991,9 @@ nsMenuFrame::Notify(nsITimer* aTimer)
   // Our timer has fired.
   if (aTimer == mOpenTimer.get()) {
     if (!mMenuOpen && mMenuParent) {
-      nsAutoString active = "";
+      nsAutoString active;
       mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, active);
-      if (active.Equals("true")) {
+      if (active.EqualsWithConversion("true")) {
         // We're still the active menu.
         OpenMenu(PR_TRUE);
       }
@@ -1011,7 +1010,7 @@ nsMenuFrame::IsDisabled()
 {
   nsAutoString disabled;
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, disabled);
-  if (disabled.Equals("true"))
+  if (disabled.EqualsWithConversion("true"))
     return PR_TRUE;
   return PR_FALSE;
 }
@@ -1021,9 +1020,9 @@ nsMenuFrame::UpdateMenuType(nsIPresContext* aPresContext)
 {
   nsAutoString value;
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::type, value);
-  if (value.Equals("checkbox"))
+  if (value.EqualsWithConversion("checkbox"))
     mType = eMenuType_Checkbox;
-  else if (value.Equals("radio")) {
+  else if (value.EqualsWithConversion("radio")) {
     mType = eMenuType_Radio;
 
     nsAutoString valueName;
@@ -1048,7 +1047,7 @@ nsMenuFrame::UpdateMenuSpecialState(nsIPresContext* aPresContext) {
 
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::checked,
                          value);
-  newChecked = (value.Equals("true"));
+  newChecked = (value.EqualsWithConversion("true"));
 
   if (newChecked == mChecked) {
     /* checked state didn't change */
@@ -1172,17 +1171,17 @@ nsMenuFrame::BuildAcceleratorText(nsString& aAccelString)
   if (!keyElement)
     return;
   
-  nsAutoString keyAtom("key");
-  nsAutoString shiftAtom("shift");
-	nsAutoString altAtom("alt");
-	nsAutoString commandAtom("command");
-  nsAutoString controlAtom("control");
+  nsAutoString keyAtom; keyAtom.AssignWithConversion("key");
+  nsAutoString shiftAtom; shiftAtom.AssignWithConversion("shift");
+	nsAutoString altAtom; altAtom.AssignWithConversion("alt");
+	nsAutoString commandAtom; commandAtom.AssignWithConversion("command");
+  nsAutoString controlAtom; controlAtom.AssignWithConversion("control");
 
 	nsAutoString shiftValue;
 	nsAutoString altValue;
 	nsAutoString commandValue;
   nsAutoString controlValue;
-	nsAutoString keyChar = " ";
+	nsAutoString keyChar; keyChar.AssignWithConversion(" ");
 	
 	keyElement->GetAttribute(keyAtom, keyChar);
 	keyElement->GetAttribute(shiftAtom, shiftValue);
@@ -1191,11 +1190,11 @@ nsMenuFrame::BuildAcceleratorText(nsString& aAccelString)
   keyElement->GetAttribute(controlAtom, controlValue);
 	  
   nsAutoString xulkey;
-  keyElement->GetAttribute(nsAutoString("xulkey"), xulkey);
-  if (xulkey.Equals("true")) {
+  keyElement->GetAttribute(NS_ConvertASCIItoUCS2("xulkey"), xulkey);
+  if (xulkey.EqualsWithConversion("true")) {
     // Set the default for the xul key modifier
 #ifdef XP_MAC
-    commandValue = "true";
+    commandValue.AssignWithConversion("true");
 #elif defined(XP_PC) || defined(NTO)
     controlValue = "true";
 #else 
@@ -1205,34 +1204,34 @@ nsMenuFrame::BuildAcceleratorText(nsString& aAccelString)
   
   PRBool prependPlus = PR_FALSE;
 
-  if(!commandValue.IsEmpty() && !commandValue.Equals("false")) {
+  if(!commandValue.IsEmpty() && !commandValue.EqualsWithConversion("false")) {
     prependPlus = PR_TRUE;
-	  aAccelString += "Ctrl"; // Hmmm. Kinda defeats the point of having an abstraction.
+	  aAccelString.AppendWithConversion("Ctrl"); // Hmmm. Kinda defeats the point of having an abstraction.
   }
 
-  if(!controlValue.IsEmpty() && !controlValue.Equals("false")) {
+  if(!controlValue.IsEmpty() && !controlValue.EqualsWithConversion("false")) {
     prependPlus = PR_TRUE;
-	  aAccelString += "Ctrl";
+	  aAccelString.AppendWithConversion("Ctrl");
   }
 
-  if(!shiftValue.IsEmpty() && !shiftValue.Equals("false")) {
+  if(!shiftValue.IsEmpty() && !shiftValue.EqualsWithConversion("false")) {
     if (prependPlus)
-      aAccelString += "+";
+      aAccelString.AppendWithConversion("+");
     prependPlus = PR_TRUE;
-    aAccelString += "Shift";
+    aAccelString.AppendWithConversion("Shift");
   }
 
-  if (!altValue.IsEmpty() && !altValue.Equals("false")) {
+  if (!altValue.IsEmpty() && !altValue.EqualsWithConversion("false")) {
 	  if (prependPlus)
-      aAccelString += "+";
+      aAccelString.AppendWithConversion("+");
     prependPlus = PR_TRUE;
-    aAccelString += "Alt";
+    aAccelString.AppendWithConversion("Alt");
   }
 
   keyChar.ToUpperCase();
   if (!keyChar.IsEmpty()) {
     if (prependPlus)
-      aAccelString += "+";
+      aAccelString.AppendWithConversion("+");
     prependPlus = PR_TRUE;
     aAccelString += keyChar;
   }
@@ -1450,7 +1449,7 @@ nsMenuFrame::GetPrefSize(nsBoxLayoutState& aState, nsSize& aSize)
       if (!element) {
         nsAutoString value;
         menulist->GetValue(value);
-        if (value == "") {
+        if (value.IsEmpty()) {
           nsCOMPtr<nsIContent> child;
           GetMenuChildrenElement(getter_AddRefs(child));
           if (child) {
diff --git a/layout/xul/base/src/nsMenuFrame.h b/layout/xul/base/src/nsMenuFrame.h
index 14ddae112dc4..b676532d7406 100644
--- a/layout/xul/base/src/nsMenuFrame.h
+++ b/layout/xul/base/src/nsMenuFrame.h
@@ -154,7 +154,7 @@ public:
 
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "Menu";
+      aResult.AssignWithConversion("Menu");
       return NS_OK;
   }
 
diff --git a/layout/xul/base/src/nsMenuPopupFrame.cpp b/layout/xul/base/src/nsMenuPopupFrame.cpp
index ff96a4e1a81d..035ea8bcb777 100644
--- a/layout/xul/base/src/nsMenuPopupFrame.cpp
+++ b/layout/xul/base/src/nsMenuPopupFrame.cpp
@@ -319,35 +319,35 @@ nsMenuPopupFrame :: AdjustPositionForAnchorAlign ( PRInt32* ioXPos, PRInt32* ioY
                                                     const nsString& aPopupAnchor, const nsString& aPopupAlign,
                                                     PRBool* outFlushWithTopBottom )
 {
-  if (aPopupAnchor.Equals("topright") && aPopupAlign.Equals("topleft")) {
+  if (aPopupAnchor.EqualsWithConversion("topright") && aPopupAlign.EqualsWithConversion("topleft")) {
     *ioXPos += inParentRect.width;
   }
-  else if (aPopupAnchor.Equals("topright") && aPopupAlign.Equals("bottomright")) {
+  else if (aPopupAnchor.EqualsWithConversion("topright") && aPopupAlign.EqualsWithConversion("bottomright")) {
     *ioXPos -= (mRect.width - inParentRect.width);
     *ioYPos -= mRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
-  else if (aPopupAnchor.Equals("bottomright") && aPopupAlign.Equals("bottomleft")) {
+  else if (aPopupAnchor.EqualsWithConversion("bottomright") && aPopupAlign.EqualsWithConversion("bottomleft")) {
     *ioXPos += inParentRect.width;
     *ioYPos -= (mRect.height - inParentRect.height);
   }
-  else if (aPopupAnchor.Equals("bottomright") && aPopupAlign.Equals("topright")) {
+  else if (aPopupAnchor.EqualsWithConversion("bottomright") && aPopupAlign.EqualsWithConversion("topright")) {
     *ioXPos -= (mRect.width - inParentRect.width);
     *ioYPos += inParentRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
-  else if (aPopupAnchor.Equals("topleft") && aPopupAlign.Equals("topright")) {
+  else if (aPopupAnchor.EqualsWithConversion("topleft") && aPopupAlign.EqualsWithConversion("topright")) {
     *ioXPos -= mRect.width;
   }
-  else if (aPopupAnchor.Equals("topleft") && aPopupAlign.Equals("bottomleft")) {
+  else if (aPopupAnchor.EqualsWithConversion("topleft") && aPopupAlign.EqualsWithConversion("bottomleft")) {
     *ioYPos -= mRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
-  else if (aPopupAnchor.Equals("bottomleft") && aPopupAlign.Equals("bottomright")) {
+  else if (aPopupAnchor.EqualsWithConversion("bottomleft") && aPopupAlign.EqualsWithConversion("bottomright")) {
     *ioXPos -= mRect.width;
     *ioYPos -= (mRect.height - inParentRect.height);
   }
-  else if (aPopupAnchor.Equals("bottomleft") && aPopupAlign.Equals("topleft")) {
+  else if (aPopupAnchor.EqualsWithConversion("bottomleft") && aPopupAlign.EqualsWithConversion("topleft")) {
     *ioYPos += inParentRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
@@ -709,10 +709,10 @@ nsMenuPopupFrame::SyncViewWithFrame(nsIPresContext* aPresContext,
   
   nsAutoString shouldDisplay, menuActive;
   mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, menuActive);
-  if (!menuActive.Equals("true")) {
+  if (!menuActive.EqualsWithConversion("true")) {
     mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, shouldDisplay);
-    if ( shouldDisplay.Equals("true") )
-      mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, "true", PR_TRUE);
+    if ( shouldDisplay.EqualsWithConversion("true") )
+      mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, NS_ConvertASCIItoUCS2("true"), PR_TRUE);
   }
 
   return NS_OK;
@@ -972,14 +972,14 @@ nsMenuPopupFrame::FindMenuWithShortcut(PRUint32 aLetter)
     // See if it's a menu item.
     if (IsValidItem(current)) {
       // Get the shortcut attribute.
-      nsAutoString shortcutKey = "";
+      nsAutoString shortcutKey;
       current->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey, shortcutKey);
       if (shortcutKey.Length() > 0) {
         // We've got something.
         char tempChar[2];
         tempChar[0] = aLetter;
         tempChar[1] = 0;
-        nsAutoString tempChar2 = tempChar;
+        nsAutoString tempChar2; tempChar2.AssignWithConversion(tempChar);
   
         if (shortcutKey.EqualsIgnoreCase(tempChar2)) {
           // We match!
@@ -1210,9 +1210,9 @@ nsMenuPopupFrame::InstallKeyboardNavigator()
   mKeyboardNavigator = new nsMenuListener(this);
   NS_IF_ADDREF(mKeyboardNavigator);
 
-  target->AddEventListener("keypress", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE); 
-  target->AddEventListener("keydown", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);  
-  target->AddEventListener("keyup", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);   
+  target->AddEventListener(NS_ConvertASCIItoUCS2("keypress"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE); 
+  target->AddEventListener(NS_ConvertASCIItoUCS2("keydown"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);  
+  target->AddEventListener(NS_ConvertASCIItoUCS2("keyup"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);   
   
   return NS_OK;
 }
@@ -1223,9 +1223,9 @@ nsMenuPopupFrame::RemoveKeyboardNavigator()
   if (!mKeyboardNavigator)
     return NS_OK;
 
-  mTarget->RemoveEventListener("keypress", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
-  mTarget->RemoveEventListener("keydown", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
-  mTarget->RemoveEventListener("keyup", (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keypress"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keydown"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
+  mTarget->RemoveEventListener(NS_ConvertASCIItoUCS2("keyup"), (nsIDOMKeyListener*)mKeyboardNavigator, PR_TRUE);
   
   NS_IF_RELEASE(mKeyboardNavigator);
 
@@ -1249,9 +1249,9 @@ nsMenuPopupFrame::IsValidItem(nsIContent* aContent)
 PRBool 
 nsMenuPopupFrame::IsDisabled(nsIContent* aContent)
 {
-  nsString disabled = "";
+  nsString disabled;
   aContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, disabled);
-  if (disabled.Equals("true"))
+  if (disabled.EqualsWithConversion("true"))
     return PR_TRUE;
   return PR_FALSE;
 }
diff --git a/layout/xul/base/src/nsMenuPopupFrame.h b/layout/xul/base/src/nsMenuPopupFrame.h
index ad39a13d27eb..81ffcd087731 100644
--- a/layout/xul/base/src/nsMenuPopupFrame.h
+++ b/layout/xul/base/src/nsMenuPopupFrame.h
@@ -132,7 +132,7 @@ public:
 
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "MenuPopup";
+      aResult.AssignWithConversion("MenuPopup");
       return NS_OK;
   }
 
diff --git a/layout/xul/base/src/nsPopupSetFrame.cpp b/layout/xul/base/src/nsPopupSetFrame.cpp
index 38b89cf13a29..7092baa8210a 100644
--- a/layout/xul/base/src/nsPopupSetFrame.cpp
+++ b/layout/xul/base/src/nsPopupSetFrame.cpp
@@ -376,9 +376,9 @@ nsPopupSetFrame::LayoutFinished(nsBoxLayoutState& aState)
     menuPopupContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::popupalign, popupAlign);
 
     if (popupAnchor.IsEmpty())
-      popupAnchor = "bottomleft";
+      popupAnchor.AssignWithConversion("bottomleft");
     if (popupAlign.IsEmpty())
-      popupAlign = "topleft";
+      popupAlign.AssignWithConversion("topleft");
    
     nsIPresContext* presContext = aState.GetPresContext();
     ((nsMenuPopupFrame*)activeChild)->SyncViewWithFrame(presContext, popupAnchor, popupAlign, mElementFrame, mXPos, mYPos);
@@ -483,7 +483,7 @@ nsPopupSetFrame::CreatePopup(nsIFrame* aElementFrame, nsIContent* aPopupContent,
   // determine if this menu is a context menu and flag it
   nsIFrame* activeChild = GetActiveChild();
   nsCOMPtr<nsIMenuParent> childPopup ( do_QueryInterface(activeChild) );
-  if ( childPopup && aPopupType.Equals("context") )
+  if ( childPopup && aPopupType.EqualsWithConversion("context") )
     childPopup->SetIsContextMenu(PR_TRUE);
 
   // Now we'll have it in our child frame list.
@@ -523,7 +523,7 @@ nsPopupSetFrame::MarkAsGenerated(nsIContent* aPopupContent)
     nsAutoString value;
     childContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, 
                                value);
-    if (value.Equals("true")) {
+    if (value.EqualsWithConversion("true")) {
       // Ungenerate this element.
       childContent->UnsetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated,
                                    PR_TRUE);
@@ -535,9 +535,9 @@ nsPopupSetFrame::MarkAsGenerated(nsIContent* aPopupContent)
   nsAutoString value;
   aPopupContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, 
                               value);
-  if (!value.Equals("true")) {
+  if (!value.EqualsWithConversion("true")) {
     // Generate this element.
-    aPopupContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, "true",
+    aPopupContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, NS_ConvertASCIItoUCS2("true"),
                                 PR_TRUE);
   }
 }
@@ -582,7 +582,7 @@ nsPopupSetFrame::ActivatePopup(PRBool aActivateFlag)
     // We wait until the last possible moment to show to avoid flashing, but we can just go
     // ahead and hide it here if we're told to (no additional stages necessary).
     if (aActivateFlag)
-      content->SetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, "true", PR_TRUE);
+      content->SetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, NS_ConvertASCIItoUCS2("true"), PR_TRUE);
     else {
       content->UnsetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, PR_TRUE);
       content->UnsetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, PR_TRUE);
diff --git a/layout/xul/base/src/nsPopupSetFrame.h b/layout/xul/base/src/nsPopupSetFrame.h
index 103fbe271988..c057bdc7bc0c 100644
--- a/layout/xul/base/src/nsPopupSetFrame.h
+++ b/layout/xul/base/src/nsPopupSetFrame.h
@@ -110,7 +110,7 @@ public:
 
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "PopupSet";
+      aResult.AssignWithConversion("PopupSet");
       return NS_OK;
   }
 
diff --git a/layout/xul/base/src/nsProgressMeterFrame.cpp b/layout/xul/base/src/nsProgressMeterFrame.cpp
index bf8da0c5ff88..7ccf31d09161 100644
--- a/layout/xul/base/src/nsProgressMeterFrame.cpp
+++ b/layout/xul/base/src/nsProgressMeterFrame.cpp
@@ -122,8 +122,8 @@ nsProgressMeterFrame::AttributeChanged(nsIPresContext* aPresContext,
       PRInt32 remainder = 100 - flex;
 
       nsAutoString leftFlex, rightFlex;
-      leftFlex.Append(flex);
-      rightFlex.Append(remainder);
+      leftFlex.AppendInt(flex);
+      rightFlex.AppendInt(remainder);
       progressBar->SetAttribute(kNameSpaceID_None, nsXULAtoms::flex, leftFlex, PR_TRUE);
       progressRemainder->SetAttribute(kNameSpaceID_None, nsXULAtoms::flex, rightFlex, PR_TRUE);
     }
diff --git a/layout/xul/base/src/nsScrollbarButtonFrame.cpp b/layout/xul/base/src/nsScrollbarButtonFrame.cpp
index 07dac3dbcda2..1af4890d83b4 100644
--- a/layout/xul/base/src/nsScrollbarButtonFrame.cpp
+++ b/layout/xul/base/src/nsScrollbarButtonFrame.cpp
@@ -156,9 +156,9 @@ nsScrollbarButtonFrame::MouseClicked()
    {
      // if our class is DecrementButton subtract the current pos by increment amount
      // if our class is IncrementButton increment the current pos by the decrement amount
-     if (value.Equals("decrement"))
+     if (value.EqualsWithConversion("decrement"))
          curpos -= increment;
-     else if (value.Equals("increment"))
+     else if (value.EqualsWithConversion("increment"))
          curpos += increment;
 
       // make sure the current positon is between the current and max positions
@@ -171,7 +171,7 @@ nsScrollbarButtonFrame::MouseClicked()
     char v[100];
     sprintf(v, "%d", curpos);
 
-    content->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, v, PR_TRUE);
+    content->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, NS_ConvertASCIItoUCS2(v), PR_TRUE);
    
    }
 
diff --git a/layout/xul/base/src/nsSliderFrame.cpp b/layout/xul/base/src/nsSliderFrame.cpp
index da1b2602a86c..12c2b19aeebc 100644
--- a/layout/xul/base/src/nsSliderFrame.cpp
+++ b/layout/xul/base/src/nsSliderFrame.cpp
@@ -181,7 +181,7 @@ nsSliderFrame::AttributeChanged(nsIPresContext* aPresContext,
           sprintf(ch,"%d", current);
  
           // set the new position but don't notify anyone. We already know
-          scrollbar->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, nsAutoString(ch), PR_FALSE);
+          scrollbar->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, NS_ConvertASCIItoUCS2(ch), PR_FALSE);
       }
   }
   
@@ -614,7 +614,7 @@ nsSliderFrame::SetCurrentPosition(nsIContent* scrollbar, nsIFrame* aThumbFrame,
   sprintf(ch,"%d", newpos);
 
   // set the new position
-  scrollbar->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, nsAutoString(ch), PR_TRUE);
+  scrollbar->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, NS_ConvertASCIItoUCS2(ch), PR_TRUE);
 
   if (DEBUG_SLIDER)
      printf("Current Pos=%s\n",ch);
diff --git a/layout/xul/base/src/nsSplitterFrame.cpp b/layout/xul/base/src/nsSplitterFrame.cpp
index 3a6dd04e1b72..4aaf9af6d47a 100644
--- a/layout/xul/base/src/nsSplitterFrame.cpp
+++ b/layout/xul/base/src/nsSplitterFrame.cpp
@@ -276,7 +276,7 @@ nsSplitterFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
         // create a spring
         nsCOMPtr<nsIContent> content;
         NS_CreateAnonymousNode(mContent, nsXULAtoms::spring, nsXULAtoms::nameSpaceID, content);
-        content->SetAttribute(kNameSpaceID_None, nsXULAtoms::flex, "100%", PR_FALSE);
+        content->SetAttribute(kNameSpaceID_None, nsXULAtoms::flex, NS_ConvertASCIItoUCS2("100%"), PR_FALSE);
         aAnonymousChildren.AppendElement(content);
 
         // a grippy
@@ -285,7 +285,7 @@ nsSplitterFrame::CreateAnonymousContent(nsIPresContext* aPresContext,
 
         // create a spring
         NS_CreateAnonymousNode(mContent, nsXULAtoms::spring, nsXULAtoms::nameSpaceID, content);
-        content->SetAttribute(kNameSpaceID_None, nsXULAtoms::flex, "100%", PR_FALSE);
+        content->SetAttribute(kNameSpaceID_None, nsXULAtoms::flex, NS_ConvertASCIItoUCS2("100%"), PR_FALSE);
         aAnonymousChildren.AppendElement(content);
      }
   }
@@ -492,7 +492,7 @@ nsSplitterFrameInner::MouseUp(nsIPresContext* aPresContext, nsGUIEvent* aEvent)
           State newState = GetState(); 
           // if the state is dragging then make it Open.
           if (newState == Dragging)
-              mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, "", PR_TRUE);
+              mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, nsAutoString(), PR_TRUE);
 
           mPressed = PR_FALSE;
 
@@ -586,7 +586,7 @@ nsSplitterFrameInner::MouseDrag(nsIPresContext* aPresContext, nsGUIEvent* aEvent
                         //printf("Collapse right\n");
                         if (GetCollapseDirection() == After) 
                         {
-                             mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, "collapsed", PR_TRUE);
+                             mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, NS_ConvertASCIItoUCS2("collapsed"), PR_TRUE);
                            
                         }
 
@@ -595,7 +595,7 @@ nsSplitterFrameInner::MouseDrag(nsIPresContext* aPresContext, nsGUIEvent* aEvent
                         //printf("Collapse left\n");
                         if (GetCollapseDirection() == Before) 
                         {
-                          mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, "collapsed", PR_TRUE);
+                          mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, NS_ConvertASCIItoUCS2("collapsed"), PR_TRUE);
                          
                         }
                     }
@@ -604,7 +604,7 @@ nsSplitterFrameInner::MouseDrag(nsIPresContext* aPresContext, nsGUIEvent* aEvent
                 // if we are not in a collapsed position and we are not dragging make sure
                 // we are dragging.
                 if (currentState != Dragging)
-                  mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, "dragging", PR_TRUE);
+                  mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, NS_ConvertASCIItoUCS2("dragging"), PR_TRUE);
 
 #ifdef REAL_TIME_DRAG
                 AdjustChildren(aPresContext);
@@ -879,7 +879,7 @@ nsSplitterFrameInner::MouseMove(nsIDOMEvent* aMouseEvent)
   if (IsMouseCaptured(mOuter->mPresContext))
     return NS_OK;
 
-  mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, "dragging", PR_TRUE);
+  mOuter->mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::state, NS_ConvertASCIItoUCS2("dragging"), PR_TRUE);
 
   RemoveListener();
   CaptureMouse(mOuter->mPresContext, PR_TRUE);
@@ -957,7 +957,7 @@ nsSplitterFrameInner::UpdateState()
             // Open -> Collapsed
             // Dragging -> Collapsed
             sibling->SetAttribute(kNameSpaceID_None, nsXULAtoms::collapsed,
-                                  "true", PR_TRUE);
+                                  NS_ConvertASCIItoUCS2("true"), PR_TRUE);
           }
         }
       }
@@ -1144,10 +1144,10 @@ nsSplitterFrameInner::SetPreferredSize(nsBoxLayoutState& aState, nsIBox* aChildB
   sprintf(ch,"%d",pref/aOnePixel);
   nsAutoString oldValue;
   content->GetAttribute(kNameSpaceID_None, attribute, oldValue);
-  if (oldValue == ch)
+  if (oldValue.EqualsWithConversion(ch))
      return;
 
-  content->SetAttribute(kNameSpaceID_None, attribute, ch, PR_FALSE);
+  content->SetAttribute(kNameSpaceID_None, attribute, NS_ConvertASCIItoUCS2(ch), PR_FALSE);
 #ifndef REAL_TIME_DRAG
   aChildBox->MarkDirty(aState);
 #else
diff --git a/layout/xul/base/src/nsSpringFrame.h b/layout/xul/base/src/nsSpringFrame.h
index 2ec9e2dd7228..5f3d2e602c8f 100644
--- a/layout/xul/base/src/nsSpringFrame.h
+++ b/layout/xul/base/src/nsSpringFrame.h
@@ -48,7 +48,7 @@ public:
 
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "Spring";
+      aResult.AssignWithConversion("Spring");
       return NS_OK;
   }
 
diff --git a/layout/xul/base/src/nsStackFrame.h b/layout/xul/base/src/nsStackFrame.h
index 705b13daaee7..ef362a1c5ba9 100644
--- a/layout/xul/base/src/nsStackFrame.h
+++ b/layout/xul/base/src/nsStackFrame.h
@@ -42,7 +42,7 @@ public:
 #ifdef NS_DEBUG
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "Stack";
+      aResult.AssignWithConversion("Stack");
       return NS_OK;
   }
 #endif
diff --git a/layout/xul/base/src/nsStdColorPicker.cpp b/layout/xul/base/src/nsStdColorPicker.cpp
index 37f4455e8c37..4edab2876ae5 100644
--- a/layout/xul/base/src/nsStdColorPicker.cpp
+++ b/layout/xul/base/src/nsStdColorPicker.cpp
@@ -195,7 +195,7 @@ NS_IMETHODIMP nsStdColorPicker::Paint(nsIPresContext * aPresContext, nsIRenderin
 
   for (i=0;i<mColors;i++)
   {
-    NS_LooseHexToRGB(mPalette[i], &color);
+    NS_LooseHexToRGB(NS_ConvertASCIItoUCS2(mPalette[i]), &color);
 
     aRenderingContext->SetColor(color);
     aRenderingContext->FillRect(col*width, row*height, width, height);
diff --git a/layout/xul/base/src/nsTabFrame.cpp b/layout/xul/base/src/nsTabFrame.cpp
index 4163fa95dcb3..2f7d30c02f97 100644
--- a/layout/xul/base/src/nsTabFrame.cpp
+++ b/layout/xul/base/src/nsTabFrame.cpp
@@ -105,17 +105,17 @@ nsTabFrame::MouseClicked(nsIPresContext* aPresContext)
       parent->ChildAt(oldIndex, *getter_AddRefs(child));
 
       // set the old tab to be unselected
-      child->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::selected, "false", PR_TRUE);
+      child->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::selected, NS_ConvertASCIItoUCS2("false"), PR_TRUE);
 
       // set the new tab to be selected
-      mContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::selected, "true", PR_TRUE);
+      mContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::selected, NS_ConvertASCIItoUCS2("true"), PR_TRUE);
    }
 
    // set the panels index
    char value[100];
    sprintf(value, "%d", index);
 
-   tabpanel->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::index, value, PR_TRUE);
+   tabpanel->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::index, NS_ConvertASCIItoUCS2(value), PR_TRUE);
 
 }
 
diff --git a/layout/xul/base/src/nsTextBoxFrame.cpp b/layout/xul/base/src/nsTextBoxFrame.cpp
index 9ea32cfd3f77..1765dfa6b472 100644
--- a/layout/xul/base/src/nsTextBoxFrame.cpp
+++ b/layout/xul/base/src/nsTextBoxFrame.cpp
@@ -107,7 +107,7 @@ nsTextBoxFrame::AttributeChanged(nsIPresContext* aPresContext,
   return NS_OK;
 }
 
-nsTextBoxFrame::nsTextBoxFrame(nsIPresShell* aShell):nsLeafBoxFrame(aShell),mTitle(""), mCropType(CropRight),mAccessKeyInfo(nsnull)
+nsTextBoxFrame::nsTextBoxFrame(nsIPresShell* aShell):nsLeafBoxFrame(aShell), mCropType(CropRight),mAccessKeyInfo(nsnull)
 {
 	mState |= NS_STATE_NEED_LAYOUT;
   NeedsRecalc();
@@ -140,17 +140,17 @@ nsTextBoxFrame::Init(nsIPresContext*  aPresContext,
   nsAutoString accesskey;
   mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey,
                          accesskey);
-  if (accesskey != "") {   
+  if (!accesskey.IsEmpty()) {   
       if (!mAccessKeyInfo)
           mAccessKeyInfo = new nsAccessKeyInfo();
 
       mAccessKeyInfo->mAccesskeyIndex = -1;
       mAccessKeyInfo->mAccesskeyIndex = mTitle.Find(accesskey, PR_TRUE);
 	  if (mAccessKeyInfo->mAccesskeyIndex == -1) {
-		  nsString tmpstring = "(" ;
+		  nsString tmpstring; tmpstring.AssignWithConversion("(");
 		  accesskey.ToUpperCase();
 		  tmpstring += accesskey;
-		  tmpstring += ")";
+		  tmpstring.AppendWithConversion(")");
 		  PRUint32 offset = mTitle.RFind("...");
 		  if ( offset != kNotFound)
 			mTitle.Insert(tmpstring,offset);
@@ -411,11 +411,11 @@ nsTextBoxFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRenderin
    mTitleWidth = aWidth;
  
    if (aWidth <= elipsisWidth) {
-       mCroppedTitle = "";
+       mCroppedTitle.SetLength(0);
        return;
    }
 
-   mCroppedTitle = ELIPSIS;
+   mCroppedTitle.AssignWithConversion(ELIPSIS);
 
    aWidth -= elipsisWidth;
 
@@ -468,7 +468,7 @@ nsTextBoxFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRenderin
            if (i == 0) 
                break;
         
-           nsString copy = "";
+           nsString copy;
            mTitle.Right(copy, length-i-1);
            mCroppedTitle = mCroppedTitle + copy;
        } 
@@ -476,10 +476,10 @@ nsTextBoxFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRenderin
 
        case CropCenter:
 
-       nsString elipsisLeft = ELIPSIS;
+       nsString elipsisLeft; elipsisLeft.AssignWithConversion(ELIPSIS);
 
        if (aWidth <= elipsisWidth) 
-         elipsisLeft = "";
+         elipsisLeft.SetLength(0);
        else
           aWidth -= elipsisWidth;
     
@@ -513,7 +513,7 @@ nsTextBoxFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRenderin
            }
 
 
-           nsString copy = "";
+           nsString copy;
 
            if (i2 > i)
               mTitle.Mid(copy, i,i2-i);
@@ -541,7 +541,7 @@ nsTextBoxFrame::UpdateAccessUnderline()
     nsAutoString accesskey;
     mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey,
                            accesskey);
-    if (accesskey == "") {
+    if (accesskey.IsEmpty()) {
         if (mAccessKeyInfo) {
             delete mAccessKeyInfo;
             mAccessKeyInfo = nsnull;
@@ -650,8 +650,8 @@ nsTextBoxFrame::GetAscent(nsBoxLayoutState& aBoxLayoutState, nscoord& aAscent)
 NS_IMETHODIMP
 nsTextBoxFrame::GetFrameName(nsString& aResult) const
 {
-  aResult = "Text[value=";
+  aResult.AssignWithConversion("Text[value=");
   aResult += mTitle;
-  aResult += "]";
+  aResult.AppendWithConversion("]");
   return NS_OK;
 }
diff --git a/layout/xul/base/src/nsTitledButtonFrame.cpp b/layout/xul/base/src/nsTitledButtonFrame.cpp
index 614f53c11126..6dec4c0db271 100644
--- a/layout/xul/base/src/nsTitledButtonFrame.cpp
+++ b/layout/xul/base/src/nsTitledButtonFrame.cpp
@@ -221,7 +221,6 @@ nsTitledButtonFrame::nsTitledButtonFrame(nsIPresShell* aShell):nsLeafBoxFrame(aS
                                                                mMinSize(0,0),
                                                                mAscent(0)
 {
-	mTitle = "";
 	mAlign = GetDefaultAlignment();
 	mCropType = CropRight;
 	mNeedsLayout = PR_TRUE;
@@ -295,7 +294,7 @@ nsTitledButtonFrame::Init(nsIPresContext*  aPresContext,
   // that UpdateAttributes doesn't double start an image load.
   nsAutoString src;
   GetImageSource(src);
-  if (!src.Equals("")) {
+  if (!src.IsEmpty()) {
     mHasImage = PR_TRUE;
   }
   mImageLoader.Init(this, UpdateImageFrame, nsnull, baseURL, src);
@@ -315,10 +314,10 @@ nsTitledButtonFrame::Init(nsIPresContext*  aPresContext,
   if (!accesskey.IsEmpty()) {    
 	  mAccesskeyIndex = mTitle.Find(accesskey, PR_TRUE);
 	  if (mAccesskeyIndex == -1) {
-		  nsString tmpstring = "(" ;
+		  nsString tmpstring; tmpstring.AssignWithConversion("(");
 		  accesskey.ToUpperCase();
 		  tmpstring += accesskey;
-		  tmpstring += ")";
+		  tmpstring.AppendWithConversion(")");
 		  PRUint32 offset = mTitle.RFind("...");
 		  if ( offset != kNotFound)
 			mTitle.Insert(tmpstring,offset);
@@ -347,7 +346,7 @@ nsTitledButtonFrame::GetImageSource(nsString& aResult)
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::src, aResult);
 
   // if the new image is empty
-  if (aResult.Equals("")) {
+  if (aResult.IsEmpty()) {
     // get the list-style-image
     const nsStyleList* myList =
       (const nsStyleList*)mStyleContext->GetStyleData(eStyleStruct_List);
@@ -447,7 +446,7 @@ nsTitledButtonFrame::UpdateImage(nsIPresContext*  aPresContext, PRBool& aResize)
 
   // see if the source changed
   // get the old image src
-  nsAutoString oldSrc ="";
+  nsAutoString oldSrc;
   mImageLoader.GetURLSpec(oldSrc);
 
   // get the new image src
@@ -457,7 +456,7 @@ nsTitledButtonFrame::UpdateImage(nsIPresContext*  aPresContext, PRBool& aResize)
    // see if the images are different
   if (!oldSrc.Equals(src)) {      
 
-        if (!src.Equals("")) {
+        if (!src.IsEmpty()) {
           mSizeFrozen = PR_FALSE;
           mHasImage = PR_TRUE;
         } else {
@@ -562,7 +561,7 @@ nsTitledButtonFrame::LayoutTitleAndImage(nsIPresContext* aPresContext,
     nscoord center_x   = rect.x + rect.width/2;
     nscoord center_y   = rect.y + rect.height/2;
 
-    mCroppedTitle = "";
+    mCroppedTitle.SetLength(0);
 
     nscoord spacing = 0;
 
@@ -695,11 +694,11 @@ nsTitledButtonFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRen
    mTitleRect.width = aWidth;
  
    if (aWidth <= elipsisWidth) {
-       mCroppedTitle = "";
+       mCroppedTitle.SetLength(0);
        return;
    }
 
-   mCroppedTitle = ELIPSIS;
+   mCroppedTitle.AssignWithConversion(ELIPSIS);
 
    aWidth -= elipsisWidth;
 
@@ -752,7 +751,7 @@ nsTitledButtonFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRen
            if (i == 0) 
                break;
         
-           nsString copy = "";
+           nsString copy;
            mTitle.Right(copy, length-i-1);
            mCroppedTitle = mCroppedTitle + copy;
        } 
@@ -760,10 +759,10 @@ nsTitledButtonFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRen
 
        case CropCenter:
 
-       nsString elipsisLeft = ELIPSIS;
+       nsString elipsisLeft; elipsisLeft.AssignWithConversion(ELIPSIS);
 
        if (aWidth <= elipsisWidth) 
-         elipsisLeft = "";
+         elipsisLeft.SetLength(0);
        else
           aWidth -= elipsisWidth;
     
@@ -797,7 +796,7 @@ nsTitledButtonFrame::CalculateTitleForWidth(nsIPresContext* aPresContext, nsIRen
            }
 
 
-           nsString copy = "";
+           nsString copy;
 
            if (i2 > i)
               mTitle.Mid(copy, i,i2-i);
@@ -1283,9 +1282,9 @@ nsTitledButtonFrame::MouseClicked (nsIPresContext* aPresContext)
 nsTitledButtonFrame::CheckState
 nsTitledButtonFrame :: StringToCheckState ( const nsString & aStateAsString )
 {
-  if ( aStateAsString.Equals(NS_STRING_TRUE) )
+  if ( aStateAsString.EqualsWithConversion(NS_STRING_TRUE) )
     return eOn;
-  else if ( aStateAsString.Equals(NS_STRING_FALSE) )
+  else if ( aStateAsString.EqualsWithConversion(NS_STRING_FALSE) )
     return eOff;
   
   // not true and not false means mixed
@@ -1303,19 +1302,19 @@ nsTitledButtonFrame :: CheckStateToString ( CheckState inState, nsString& outSta
 {
   switch ( inState ) {
     case eOn:
-      outStateAsString = NS_STRING_TRUE;
+      outStateAsString.AssignWithConversion(NS_STRING_TRUE);
 	  break;
 
     case eOff:
-      outStateAsString = NS_STRING_FALSE;
+      outStateAsString.AssignWithConversion(NS_STRING_FALSE);
       break;
  
     case eMixed:
-      outStateAsString = "2";
+      outStateAsString.AssignWithConversion("2");
       break;
 
     case eUnset:
-      outStateAsString = "";
+      outStateAsString.SetLength(0);
   }
 } // CheckStateToString
 
@@ -1551,8 +1550,8 @@ nsTitledButtonFrame::CacheSizes(nsBoxLayoutState& aBoxLayoutState)
 NS_IMETHODIMP
 nsTitledButtonFrame::GetFrameName(nsString& aResult) const
 {
-  aResult = "TitledButton[value=";
+  aResult.AssignWithConversion("TitledButton[value=");
   aResult += mTitle;
-  aResult += "]";
+  aResult.AppendWithConversion("]");
   return NS_OK;
 }
diff --git a/layout/xul/base/src/nsToolbarDragListener.cpp b/layout/xul/base/src/nsToolbarDragListener.cpp
index 4e3f8594264c..0a789b8006e0 100644
--- a/layout/xul/base/src/nsToolbarDragListener.cpp
+++ b/layout/xul/base/src/nsToolbarDragListener.cpp
@@ -201,8 +201,8 @@ nsToolbarDragListener :: ItemMouseIsOver ( nsIDOMEvent* aDragEvent, nscoord* out
           nsCOMPtr<nsIDOMElement> domElement ( do_QueryInterface(content) );
           if ( domElement ) {
             nsAutoString value;
-            domElement->GetAttribute(nsAutoString("container"), value);  // can't use an atom here =(
-            isContainer = value.Equals("true");
+            domElement->GetAttribute(NS_ConvertASCIItoUCS2("container"), value);  // can't use an atom here =(
+            isContainer = value.EqualsWithConversion("true");
           }
           else
             NS_WARNING("Not a DOM element");        
@@ -292,10 +292,10 @@ nsToolbarDragListener::DragOver(nsIDOMEvent* aDragEvent)
 
       	// need the cast, because on some platforms, PR[U]int32 != long, but we're using "%ld"
       sprintf(buffer, "%ld", NS_STATIC_CAST(long, xLoc));
-      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, buffer, PR_TRUE );
+      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, NS_ConvertASCIItoUCS2(buffer), PR_TRUE );
       sprintf(buffer, "%ld", NS_STATIC_CAST(long, beforeIndex));
-      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, buffer, PR_FALSE );
-      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropOn, onChild ? "true" : "false", PR_FALSE );
+      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, NS_ConvertASCIItoUCS2(buffer), PR_FALSE );
+      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropOn, NS_ConvertASCIItoUCS2(onChild ? "true" : "false"), PR_FALSE );
     }
     
     // cache the current drop location
@@ -343,9 +343,9 @@ nsToolbarDragListener::DragExit(nsIDOMEvent* aDragEvent)
     // AttributeChanged() about that attribute.
     char buffer[10];
     sprintf(buffer, "%d", -1);
-    myContent->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, buffer, PR_TRUE );
-    myContent->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, buffer, PR_FALSE );
-    myContent->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddTriggerRepaint, "1", PR_TRUE );
+    myContent->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, NS_ConvertASCIItoUCS2(buffer), PR_TRUE );
+    myContent->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, NS_ConvertASCIItoUCS2(buffer), PR_FALSE );
+    myContent->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddTriggerRepaint, NS_ConvertASCIItoUCS2("1"), PR_TRUE );
     
     // reset the current drop location
     mCurrentDropLoc = -1;
diff --git a/layout/xul/base/src/nsToolbarFrame.cpp b/layout/xul/base/src/nsToolbarFrame.cpp
index 48962844224f..85a6469ca1a6 100644
--- a/layout/xul/base/src/nsToolbarFrame.cpp
+++ b/layout/xul/base/src/nsToolbarFrame.cpp
@@ -175,8 +175,8 @@ nsToolbarFrame :: ~nsToolbarFrame ( )
 
   // NOTE: the last Remove will delete the drag listener
   if ( receiver ) {
-    receiver->RemoveEventListener("dragover", mDragListener, PR_TRUE);
-    receiver->RemoveEventListener("dragexit", mDragListener, PR_TRUE);
+    receiver->RemoveEventListener(NS_ConvertASCIItoUCS2("dragover"), mDragListener, PR_TRUE);
+    receiver->RemoveEventListener(NS_ConvertASCIItoUCS2("dragexit"), mDragListener, PR_TRUE);
   }
 }
 
@@ -205,8 +205,8 @@ nsToolbarFrame::Init ( nsIPresContext*  aPresContext, nsIContent* aContent,
   // with enough info to determine where the drop would happen so that JS down the 
   // line can do the right thing.
   mDragListener = new nsToolbarDragListener(this, aPresContext);
-  receiver->AddEventListener("dragover", mDragListener, PR_TRUE);
-  receiver->AddEventListener("dragexit", mDragListener, PR_TRUE);
+  receiver->AddEventListener(NS_ConvertASCIItoUCS2("dragover"), mDragListener, PR_TRUE);
+  receiver->AddEventListener(NS_ConvertASCIItoUCS2("dragexit"), mDragListener, PR_TRUE);
 
 #if 0 //TEMP_HACK_FOR_BUG_11291
   // Ok, this is a hack until Ender lands. We need to have a mouse listener on text widgets
diff --git a/layout/xul/base/src/nsToolbarFrame.h b/layout/xul/base/src/nsToolbarFrame.h
index a20b5e89c725..a98d17a44093 100644
--- a/layout/xul/base/src/nsToolbarFrame.h
+++ b/layout/xul/base/src/nsToolbarFrame.h
@@ -98,7 +98,7 @@ public:
 
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "Toolbar";
+      aResult.AssignWithConversion("Toolbar");
       return NS_OK;
   }
 
diff --git a/layout/xul/base/src/nsToolboxFrame.h b/layout/xul/base/src/nsToolboxFrame.h
index 36630d80648e..e9737b83187e 100644
--- a/layout/xul/base/src/nsToolboxFrame.h
+++ b/layout/xul/base/src/nsToolboxFrame.h
@@ -72,7 +72,7 @@ public:
 
   NS_IMETHOD GetFrameName(nsString& aResult) const
   {
-      aResult = "Toolbox";
+      aResult.AssignWithConversion("Toolbox");
       return NS_OK;
   }
 
diff --git a/layout/xul/base/src/nsTreeCellFrame.cpp b/layout/xul/base/src/nsTreeCellFrame.cpp
index 48789d6cee72..ca5b3c81fdd8 100644
--- a/layout/xul/base/src/nsTreeCellFrame.cpp
+++ b/layout/xul/base/src/nsTreeCellFrame.cpp
@@ -84,7 +84,7 @@ nsTreeCellFrame::Init(nsIPresContext*  aPresContext,
   nsresult result = aContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::allowevents, attrValue);
   attrValue.ToLowerCase();
   PRBool allowEvents =  (result == NS_CONTENT_ATTR_NO_VALUE ||
-					    (result == NS_CONTENT_ATTR_HAS_VALUE && attrValue.Equals("true")));
+					    (result == NS_CONTENT_ATTR_HAS_VALUE && attrValue.EqualsWithConversion("true")));
   SetAllowEvents(allowEvents);
 
   // Determine if we're a column header or not.
@@ -171,7 +171,7 @@ nsTreeCellFrame::GetFrameForPoint(nsIPresContext* aPresContext,
         // This allows selective overriding for subcontent.
         nsAutoString value;
         content->GetAttribute(kNameSpaceID_None, nsXULAtoms::allowevents, value);
-        if (value.Equals("true"))
+        if (value.EqualsWithConversion("true"))
           return result;
       }
     }
@@ -354,18 +354,18 @@ nsTreeCellFrame::ToggleOpenClose()
 	  
 	  // Take the tree item content and toggle the value of its open attribute.
 	  nsAutoString attrValue;
-    treeItem->GetAttribute("open", attrValue);
+    treeItem->GetAttribute(NS_ConvertASCIItoUCS2("open"), attrValue);
     attrValue.ToLowerCase();
-    PRBool isExpanded = (attrValue.Equals("true"));
+    PRBool isExpanded = (attrValue.EqualsWithConversion("true"));
     if (isExpanded)
 	  {
 		  // We're collapsing and need to remove frames from the flow.
-		  treeItem->RemoveAttribute("open");
+		  treeItem->RemoveAttribute(NS_ConvertASCIItoUCS2("open"));
 	  }
 	  else
 	  {
 		  // We're expanding and need to add frames to the flow.
-		  treeItem->SetAttribute("open", "true");
+		  treeItem->SetAttribute(NS_ConvertASCIItoUCS2("open"), NS_ConvertASCIItoUCS2("true"));
 	  }
   }
 }
@@ -389,12 +389,12 @@ nsTreeCellFrame::Open()
 	  
 	  // Take the tree item content and toggle the value of its open attribute.
 	  nsAutoString attrValue;
-    treeItem->GetAttribute("open", attrValue);
+    treeItem->GetAttribute(NS_ConvertASCIItoUCS2("open"), attrValue);
     attrValue.ToLowerCase();
-    PRBool isExpanded = (attrValue.Equals("true"));
+    PRBool isExpanded = (attrValue.EqualsWithConversion("true"));
     if (!isExpanded) {
 		  // We're expanding and need to add frames to the flow.
-		  treeItem->SetAttribute("open", "true");
+		  treeItem->SetAttribute(NS_ConvertASCIItoUCS2("open"), NS_ConvertASCIItoUCS2("true"));
 	  }
   }
 }
@@ -418,12 +418,12 @@ nsTreeCellFrame::Close()
 	  
 	  // Take the tree item content and toggle the value of its open attribute.
 	  nsAutoString attrValue;
-    treeItem->GetAttribute("open", attrValue);
+    treeItem->GetAttribute(NS_ConvertASCIItoUCS2("open"), attrValue);
     attrValue.ToLowerCase();
-    PRBool isExpanded = (attrValue.Equals("true"));
+    PRBool isExpanded = (attrValue.EqualsWithConversion("true"));
     if (isExpanded) {
 		  // We're expanding and need to add frames to the flow.
-		  treeItem->RemoveAttribute("open");
+		  treeItem->RemoveAttribute(NS_ConvertASCIItoUCS2("open"));
 	  }
   }
 }
@@ -449,9 +449,9 @@ void nsTreeCellFrame::Hover(nsIPresContext* aPresContext, PRBool isHover, PRBool
   if (isHover)
 	{
 		// We're selecting the node.
-		mContent->SetAttribute(kNameSpaceID_None, kHoverAtom, "true", notifyForReflow);
-    rowContent->SetAttribute(kNameSpaceID_None, kHoverAtom, "true", notifyForReflow);
-    itemContent->SetAttribute(kNameSpaceID_None, kHoverAtom, "true", notifyForReflow);
+		mContent->SetAttribute(kNameSpaceID_None, kHoverAtom, NS_ConvertASCIItoUCS2("true"), notifyForReflow);
+    rowContent->SetAttribute(kNameSpaceID_None, kHoverAtom, NS_ConvertASCIItoUCS2("true"), notifyForReflow);
+    itemContent->SetAttribute(kNameSpaceID_None, kHoverAtom, NS_ConvertASCIItoUCS2("true"), notifyForReflow);
 	}
 	else
 	{
diff --git a/layout/xul/base/src/nsTreeFrame.cpp b/layout/xul/base/src/nsTreeFrame.cpp
index 477ecc546d36..2192428e6c74 100644
--- a/layout/xul/base/src/nsTreeFrame.cpp
+++ b/layout/xul/base/src/nsTreeFrame.cpp
@@ -139,7 +139,7 @@ void nsTreeFrame::SetSelection(nsIPresContext* aPresContext, nsTreeCellFrame* aF
   nsCOMPtr<nsIDOMXULElement> itemElement = do_QueryInterface(itemContent);
 
   nsCOMPtr<nsIAtom> kSuppressSelectChange = dont_AddRef(NS_NewAtom("suppressonselect"));
-  mContent->SetAttribute(kNameSpaceID_None, kSuppressSelectChange, "true", PR_FALSE);
+  mContent->SetAttribute(kNameSpaceID_None, kSuppressSelectChange, NS_ConvertASCIItoUCS2("true"), PR_FALSE);
   treeElement->SelectItem(itemElement);
   mContent->UnsetAttribute(kNameSpaceID_None, kSuppressSelectChange, PR_FALSE);
   treeElement->SelectCell(cellElement);
@@ -161,7 +161,7 @@ void nsTreeFrame::ToggleSelection(nsIPresContext* aPresContext, nsTreeCellFrame*
   nsCOMPtr<nsIDOMXULElement> itemElement = do_QueryInterface(itemContent);
 
   nsCOMPtr<nsIAtom> kSuppressSelectChange = dont_AddRef(NS_NewAtom("suppressonselect"));
-  mContent->SetAttribute(kNameSpaceID_None, kSuppressSelectChange, "true", PR_FALSE);
+  mContent->SetAttribute(kNameSpaceID_None, kSuppressSelectChange, NS_ConvertASCIItoUCS2("true"), PR_FALSE);
   treeElement->ToggleItemSelection(itemElement);
   mContent->UnsetAttribute(kNameSpaceID_None, kSuppressSelectChange, PR_FALSE);
   treeElement->ToggleCellSelection(cellElement);
@@ -380,7 +380,7 @@ NS_IMETHODIMP
 nsTreeFrame::Destroy(nsIPresContext* aPresContext)
 {
   nsCOMPtr<nsIDOMEventReceiver> target = do_QueryInterface(mContent);
-  target->RemoveEventListener("mousedown", mTwistyListener, PR_TRUE); 
+  target->RemoveEventListener(NS_ConvertASCIItoUCS2("mousedown"), mTwistyListener, PR_TRUE); 
 	mTwistyListener = nsnull;
   return nsTableFrame::Destroy(aPresContext);
 }
@@ -487,11 +487,11 @@ nsTreeFrame::Init(nsIPresContext*  aPresContext,
 
   nsCOMPtr<nsIDOMEventReceiver> target = do_QueryInterface(mContent);
   
-  target->AddEventListener("mousedown", mTwistyListener, PR_TRUE); 
+  target->AddEventListener(NS_ConvertASCIItoUCS2("mousedown"), mTwistyListener, PR_TRUE); 
 
   nsAutoString value;
   nsCOMPtr<nsIDOMElement> element = do_QueryInterface(mContent);
-  element->GetAttribute("rows", value);
+  element->GetAttribute(NS_ConvertASCIItoUCS2("rows"), value);
 
   if (!value.IsEmpty()) {
     PRInt32 dummy;
@@ -514,7 +514,7 @@ nsTreeFrame::ContainsFlexibleColumn(PRInt32 aStartIndex, PRInt32 aEndIndex,
     if (colContent) {
       nsAutoString fixedValue;
       colContent->GetAttribute(kNameSpaceID_None, fixedAtom, fixedValue);
-      if (!fixedValue.Equals("true")) {
+      if (!fixedValue.EqualsWithConversion("true")) {
         // We are a proportional column.
         if (aResult)
           *aResult = result;
diff --git a/layout/xul/base/src/nsTreeItemDragCapturer.cpp b/layout/xul/base/src/nsTreeItemDragCapturer.cpp
index 94f7a6216e1b..1c7139fbc7ee 100644
--- a/layout/xul/base/src/nsTreeItemDragCapturer.cpp
+++ b/layout/xul/base/src/nsTreeItemDragCapturer.cpp
@@ -164,8 +164,8 @@ nsTreeItemDragCapturer :: ComputeDropPosition ( nsIDOMEvent* aDragEvent, nscoord
   nsCOMPtr<nsIDOMElement> treeItemNode ( do_QueryInterface(treeItemContent) );
   if ( treeItemNode ) {
     nsAutoString value;
-    treeItemNode->GetAttribute(nsAutoString("container"), value);  // can't use an atom here =(
-    isContainer = value.Equals("true");
+    treeItemNode->GetAttribute(NS_ConvertASCIItoUCS2("container"), value);  // can't use an atom here =(
+    isContainer = value.EqualsWithConversion("true");
   }
   else
     NS_WARNING("Not a DOM element");
@@ -231,9 +231,9 @@ nsTreeItemDragCapturer::DragOver(nsIDOMEvent* aDragEvent)
 
       	// need the cast, because on some platforms, PR[U]int32 != long, but we're using "%ld"
       sprintf(buffer, "%d", yLoc);
-      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, buffer, PR_TRUE );
-      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, beforeMe ? "true" : "false", PR_FALSE );
-      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropOn, onMe ? "true" : "false", PR_TRUE );
+      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, NS_ConvertASCIItoUCS2(buffer), PR_TRUE );
+      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, NS_ConvertASCIItoUCS2(beforeMe ? "true" : "false"), PR_FALSE );
+      content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropOn, NS_ConvertASCIItoUCS2(onMe ? "true" : "false"), PR_TRUE );
     }
     
     // cache the current drop location
@@ -264,10 +264,10 @@ nsTreeItemDragCapturer::DragExit(nsIDOMEvent* aDragEvent)
     // AttributeChanged() about that attribute.
     char buffer[10];
     sprintf(buffer, "%d", kNoDropLoc);
-    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, buffer, PR_TRUE );
-    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, "false", PR_TRUE );
-    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropOn, "false", PR_TRUE );
-    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddTriggerRepaintRestore, "1", PR_TRUE );  
+    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocationCoord, NS_ConvertASCIItoUCS2(buffer), PR_TRUE );
+    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropLocation, NS_ConvertASCIItoUCS2("false"), PR_TRUE );
+    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddDropOn, NS_ConvertASCIItoUCS2("false"), PR_TRUE );
+    content->SetAttribute ( kNameSpaceID_None, nsXULAtoms::ddTriggerRepaintRestore, NS_ConvertASCIItoUCS2("1"), PR_TRUE );  
   }
   
   // cache the current drop location
diff --git a/layout/xul/base/src/nsTreeRowFrame.cpp b/layout/xul/base/src/nsTreeRowFrame.cpp
index c826dd5bf70c..ad3cb489a5d1 100644
--- a/layout/xul/base/src/nsTreeRowFrame.cpp
+++ b/layout/xul/base/src/nsTreeRowFrame.cpp
@@ -309,7 +309,7 @@ nsTreeRowFrame::HandleHeaderDragEvent(nsIPresContext* aPresContext,
     if (colContent) {
       nsAutoString fixedValue;
       colContent->GetAttribute(kNameSpaceID_None, fixedAtom, fixedValue);
-      if (!fixedValue.Equals("true")) {
+      if (!fixedValue.EqualsWithConversion("true")) {
         // We are a proportional column and should be annotated with our current
         // width.
         PRInt32 colWidth = treeFrame->GetColumnWidth(i);
@@ -328,7 +328,7 @@ nsTreeRowFrame::HandleHeaderDragEvent(nsIPresContext* aPresContext,
         PRInt32 colWidth = colWidths[i];
         char ch[100];
         sprintf(ch,"%d*", colWidth);
-        nsAutoString propColWidth(ch);
+        nsAutoString propColWidth; propColWidth.AssignWithConversion(ch);
         colContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::width, propColWidth,
                                  PR_TRUE);
       }
@@ -379,7 +379,7 @@ nsTreeRowFrame::HandleHeaderDragEvent(nsIPresContext* aPresContext,
       colWidth = colWidths[colX] + mod;
      
       sprintf(ch,"%d*", colWidth);
-      nsAutoString propColWidth(ch);
+      nsAutoString propColWidth; propColWidth.AssignWithConversion(ch);
       
       colFrame->GetContent(getter_AddRefs(colContent));
       if (colContent) {
@@ -395,7 +395,7 @@ nsTreeRowFrame::HandleHeaderDragEvent(nsIPresContext* aPresContext,
   if (remaining != 0 && colContent) {
     colWidth += remaining;
     sprintf(ch,"%d*", colWidth);
-    nsAutoString propColWidth(ch);
+    nsAutoString propColWidth; propColWidth.AssignWithConversion(ch);
     colContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::width, propColWidth,
                              PR_TRUE);
 
@@ -412,7 +412,7 @@ nsTreeRowFrame::HandleHeaderDragEvent(nsIPresContext* aPresContext,
     
     colWidth = flexWidth - delta;
     sprintf(ch,"%d*", colWidth);
-    nsAutoString propColWidth(ch);
+    nsAutoString propColWidth; propColWidth.AssignWithConversion(ch);
     flexContent->SetAttribute(kNameSpaceID_None, nsHTMLAtoms::width, propColWidth,
                               PR_TRUE); // NOW we send the notification that causes the reflow.
   }
diff --git a/layout/xul/base/src/nsTreeRowGroupFrame.cpp b/layout/xul/base/src/nsTreeRowGroupFrame.cpp
index 1f09c2886a9d..1ec4780c51bd 100644
--- a/layout/xul/base/src/nsTreeRowGroupFrame.cpp
+++ b/layout/xul/base/src/nsTreeRowGroupFrame.cpp
@@ -131,8 +131,8 @@ nsTreeRowGroupFrame::~nsTreeRowGroupFrame()
 
   // NOTE: the last Remove will delete the drag capturer
   if ( receiver ) {
-    receiver->RemoveEventListener("dragover", mDragCapturer, PR_TRUE);
-    receiver->RemoveEventListener("dragexit", mDragCapturer, PR_TRUE);
+    receiver->RemoveEventListener(NS_ConvertASCIItoUCS2("dragover"), mDragCapturer, PR_TRUE);
+    receiver->RemoveEventListener(NS_ConvertASCIItoUCS2("dragexit"), mDragCapturer, PR_TRUE);
   }
   
   NS_IF_RELEASE(mContentChain);
@@ -214,8 +214,8 @@ nsTreeRowGroupFrame::Init ( nsIPresContext*  aPresContext, nsIContent* aContent,
     // with enough info to determine where the drop would happen so that JS down the 
     // line can do the right thing.
     mDragCapturer = new nsTreeItemDragCapturer(this, aPresContext);
-    receiver->AddEventListener("dragover", mDragCapturer, PR_TRUE);
-    receiver->AddEventListener("dragexit", mDragCapturer, PR_TRUE);
+    receiver->AddEventListener(NS_ConvertASCIItoUCS2("dragover"), mDragCapturer, PR_TRUE);
+    receiver->AddEventListener(NS_ConvertASCIItoUCS2("dragexit"), mDragCapturer, PR_TRUE);
   }
   
   return rv;
@@ -551,7 +551,7 @@ nsTreeRowGroupFrame::FindRowContentAtIndex(PRInt32& aIndex,
       nsCOMPtr<nsIAtom> openAtom = dont_AddRef(NS_NewAtom("open"));
       nsAutoString isOpen;
       childContent->GetAttribute(kNameSpaceID_None, openAtom, isOpen);
-      if (isOpen.Equals("true")) {
+      if (isOpen.EqualsWithConversion("true")) {
         // Find the <treechildren> node.
         PRInt32 childContentCount;
         nsCOMPtr<nsIContent> grandChild;
@@ -627,7 +627,7 @@ nsTreeRowGroupFrame::FindPreviousRowContent(PRInt32& aDelta, nsIContent* aUpward
       nsCOMPtr<nsIAtom> openAtom = dont_AddRef(NS_NewAtom("open"));
       nsAutoString isOpen;
       childContent->GetAttribute(kNameSpaceID_None, openAtom, isOpen);
-      if (isOpen.Equals("true")) {
+      if (isOpen.EqualsWithConversion("true")) {
         // Find the <treechildren> node.
         PRInt32 childContentCount;
         nsCOMPtr<nsIContent> grandChild;
@@ -695,7 +695,7 @@ nsTreeRowGroupFrame::ComputeTotalRowCount(PRInt32& aCount, nsIContent* aParent)
       nsCOMPtr<nsIContent> parent;
       childContent->GetParent(*getter_AddRefs(parent));
       parent->GetAttribute(kNameSpaceID_None, openAtom, isOpen);
-      if (isOpen.Equals("true"))
+      if (isOpen.EqualsWithConversion("true"))
       ComputeTotalRowCount(aCount, childContent);
     }
   }
@@ -828,7 +828,7 @@ nsTreeRowGroupFrame::PagedUpDown()
 #ifdef DEBUG_tree
     printf("PagedUpDown, setting increment to %d\n", rowGroupCount);
 #endif
-    scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::pageincrement, nsAutoString(ch), PR_FALSE);
+    scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::pageincrement, NS_ConvertASCIItoUCS2(ch), PR_FALSE);
   }
 
   return NS_OK;
@@ -847,12 +847,12 @@ nsTreeRowGroupFrame::SetScrollbarFrame(nsIPresContext* aPresContext, nsIFrame* a
   aFrame->GetContent(getter_AddRefs(scrollbarContent));
   
   nsAutoString scrollFactor;
-  scrollFactor.Append(SCROLL_FACTOR);
+  scrollFactor.AppendWithConversion(SCROLL_FACTOR);
 
-  scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, "0", PR_FALSE);
+  scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, NS_ConvertASCIItoUCS2("0"), PR_FALSE);
   scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::increment, scrollFactor, PR_FALSE);
-  scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::pageincrement, "1", PR_FALSE);
-  scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::maxpos, "5000", PR_FALSE);
+  scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::pageincrement, NS_ConvertASCIItoUCS2("1"), PR_FALSE);
+  scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::maxpos, NS_ConvertASCIItoUCS2("5000"), PR_FALSE);
 
   nsIFrame* result;
   nsScrollbarButtonFrame::GetChildWithTag(aPresContext, nsXULAtoms::slider, aFrame, result);
@@ -1496,7 +1496,7 @@ void nsTreeRowGroupFrame::OnContentRemoved(nsIPresContext* aPresContext,
      mCurrentIndex--;
      nsAutoString indexStr;
      PRInt32 pixelIndex = mCurrentIndex * SCROLL_FACTOR;
-     indexStr.Append(pixelIndex);
+     indexStr.AppendInt(pixelIndex);
     
      nsCOMPtr<nsIContent> scrollbarContent;
      mScrollbar->GetContent(getter_AddRefs(scrollbarContent));
@@ -1564,7 +1564,7 @@ nsTreeRowGroupFrame::ReflowScrollbar(nsIPresContext* aPresContext)
     if (count < pageRowCount) {
       // first set the position to 0 so that all visible content
       // scrolls into view
-      value.Append(0);
+      value.AppendInt(0);
       scrollbarContent->SetAttribute(kNameSpaceID_None,
                                      nsXULAtoms::curpos,
                                      value, PR_TRUE);
@@ -1578,7 +1578,7 @@ nsTreeRowGroupFrame::ReflowScrollbar(nsIPresContext* aPresContext)
                                      nsXULAtoms::curpos, value);
     }
    
-    if (nukeScrollbar || (value.Equals("0") && !mIsFull)) {
+    if (nukeScrollbar || (value.EqualsWithConversion("0") && !mIsFull)) {
       
       // clear the scrollbar out of the event state manager so that the
       // event manager doesn't send events to the destroyed scrollbar frames
@@ -1629,7 +1629,7 @@ nsTreeRowGroupFrame::ReflowScrollbar(nsIPresContext* aPresContext)
     rowCount *= SCROLL_FACTOR;
     char ch[100];
     sprintf(ch,"%d", rowCount);
-    maxpos = ch;
+    maxpos.AssignWithConversion(ch);
   }
 
   // Make sure our position is accurate
@@ -1673,7 +1673,7 @@ void nsTreeRowGroupFrame::CreateScrollbar(nsIPresContext* aPresContext)
     nsCOMPtr<nsIDOMDocument> document(do_QueryInterface(idocument));
 
     nsCOMPtr<nsIDOMElement> node;
-    document->CreateElement("scrollbar",getter_AddRefs(node));
+    document->CreateElement(NS_ConvertASCIItoUCS2("scrollbar"),getter_AddRefs(node));
 
     nsCOMPtr<nsIContent> content = do_QueryInterface(node);
     content->SetDocument(idocument, PR_FALSE);
@@ -1684,7 +1684,7 @@ void nsTreeRowGroupFrame::CreateScrollbar(nsIPresContext* aPresContext)
       xulContent->SetAnonymousState(PR_TRUE); // Mark as anonymous to keep events from getting out.
     
     nsCOMPtr<nsIAtom> align = dont_AddRef(NS_NewAtom("align"));
-    content->SetAttribute(kNameSpaceID_None, align, "vertical", PR_FALSE);
+    content->SetAttribute(kNameSpaceID_None, align, NS_ConvertASCIItoUCS2("vertical"), PR_FALSE);
     
     nsIFrame* aResult;
     mFrameConstructor->CreateTreeWidgetContent(aPresContext, this, nsnull, content,
@@ -1846,7 +1846,7 @@ nsTreeRowGroupFrame::EnsureRowIsVisible(PRInt32 aRowIndex)
 #endif
   
   scrollTo *= SCROLL_FACTOR;
-  value.Append(scrollTo);
+  value.AppendInt(scrollTo);
   scrollbarContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos,
                                  value, PR_TRUE);
 
@@ -1913,7 +1913,7 @@ void nsTreeRowGroupFrame::ScrollByLines(nsIPresContext* aPresContext,
 
   scrollTo *= SCROLL_FACTOR;
   nsAutoString value;
-  value.Append(scrollTo);
+  value.AppendInt(scrollTo);
 
   nsCOMPtr<nsIContent> scrollbarContent;
   mScrollbar->GetContent(getter_AddRefs(scrollbarContent));
@@ -2136,7 +2136,7 @@ nsTreeRowGroupFrame :: AttributeChanged ( nsIPresContext* aPresContext, nsIConte
     nsAutoString attribute;
     aChild->GetAttribute ( kNameSpaceID_None, aAttribute, attribute );
     attribute.ToLowerCase();
-    mDropOnContainer = attribute.Equals("true");
+    mDropOnContainer = attribute.EqualsWithConversion("true");
   }
   else
     rv = nsTableRowGroupFrame::AttributeChanged ( aPresContext, aChild, aNameSpaceID, aAttribute, aHint );
@@ -2443,9 +2443,9 @@ nsTreeRowGroupFrame :: IsOpenContainer ( ) const
   nsCOMPtr<nsIDOMElement> me ( do_QueryInterface(mContent) );
   if ( me ) {
     nsAutoString isContainer, isOpen;
-    me->GetAttribute(nsAutoString("container"), isContainer);
-    me->GetAttribute(nsAutoString("open"), isOpen);
-    isOpenContainer = (isContainer.Equals("true") && isOpen.Equals("true"));
+    me->GetAttribute(NS_ConvertASCIItoUCS2("container"), isContainer);
+    me->GetAttribute(NS_ConvertASCIItoUCS2("open"), isOpen);
+    isOpenContainer = (isContainer.EqualsWithConversion("true") && isOpen.EqualsWithConversion("true"));
   }
 
   return isOpenContainer;
diff --git a/layout/xul/base/src/nsTreeTwistyListener.cpp b/layout/xul/base/src/nsTreeTwistyListener.cpp
index 43be1c8abc00..10e38837e92f 100644
--- a/layout/xul/base/src/nsTreeTwistyListener.cpp
+++ b/layout/xul/base/src/nsTreeTwistyListener.cpp
@@ -88,11 +88,11 @@ nsTreeTwistyListener::MouseDown(nsIDOMEvent* aEvent)
 
   nsAutoString tagName;
   element->GetTagName(tagName);
-  if (tagName.Equals("titledbutton")) {
+  if (tagName.EqualsWithConversion("titledbutton")) {
     // Find out if we're the twisty.
     nsAutoString classAttr;
-    element->GetAttribute("class", classAttr);
-    if (classAttr.Equals("twisty")) {
+    element->GetAttribute(NS_ConvertASCIItoUCS2("class"), classAttr);
+    if (classAttr.EqualsWithConversion("twisty")) {
       // Retrieve the parent treeitem.
       nsCOMPtr<nsIDOMElement> treeItem;
       GetTreeItem(element, getter_AddRefs(treeItem));
@@ -106,10 +106,10 @@ nsTreeTwistyListener::MouseDown(nsIDOMEvent* aEvent)
       aEvent->PreventDefault();
 
       nsAutoString open;
-      treeItem->GetAttribute("open", open);
-      if (open.Equals("true"))
-        treeItem->RemoveAttribute("open");
-      else treeItem->SetAttribute("open", "true");
+      treeItem->GetAttribute(NS_ConvertASCIItoUCS2("open"), open);
+      if (open.EqualsWithConversion("true"))
+        treeItem->RemoveAttribute(NS_ConvertASCIItoUCS2("open"));
+      else treeItem->SetAttribute(NS_ConvertASCIItoUCS2("open"), NS_ConvertASCIItoUCS2("true"));
     }
   }
   return NS_OK;
diff --git a/layout/xul/content/src/nsXULAtoms.cpp b/layout/xul/content/src/nsXULAtoms.cpp
index 9eed84f46e4f..653e4f1f20c0 100644
--- a/layout/xul/content/src/nsXULAtoms.cpp
+++ b/layout/xul/content/src/nsXULAtoms.cpp
@@ -47,7 +47,7 @@ void nsXULAtoms::AddRefAtoms() {
     */
     if (NS_SUCCEEDED(NS_NewNameSpaceManager(&gNameSpaceManager))) {
 //    gNameSpaceManager->CreateRootNameSpace(namespace);
-      nsAutoString nameSpace(kXULNameSpace);
+      nsAutoString nameSpace; nameSpace.AssignWithConversion(kXULNameSpace);
       gNameSpaceManager->RegisterNameSpace(nameSpace, nameSpaceID);
     } else {
       NS_ASSERTION(0, "failed to create xul atoms namespace manager");