Make XML serializer output an encoding="..." which matches the actual encoding

it's serializing to.  Bug 361933, r+sr=sicking

content/base/public/nsIDOMSerializer.idl

@@ -67,7 +67,8 @@ interface nsIDOMSerializer : nsISupports
    *             be any node, including a Document.
    * @param stream The byte stream to which the subtree is serialized.
    * @param charset The name of the character set to use for the encoding
-   *                to a byte stream.
+   *                to a byte stream.  If this string is empty and root is
+   *                a document, the document's character set will be used.
    */
   void serializeToStream(in nsIDOMNode root, in nsIOutputStream stream,
                          in AUTF8String charset);

content/base/src/nsDOMSerializer.cpp

@@ -148,7 +148,7 @@ nsDOMSerializer::SerializeToStream(nsIDOMNode *aRoot,
 {
   NS_ENSURE_ARG_POINTER(aRoot);
   NS_ENSURE_ARG_POINTER(aStream);
-  // The charset arg can be null, in which case we get the document's
+  // The charset arg can be empty, in which case we get the document's
   // charset and use that when serializing.
 
   if (!nsContentUtils::CanCallerAccess(aRoot)) {

content/base/src/nsHTMLContentSerializer.cpp

@@ -145,7 +145,7 @@ nsHTMLContentSerializer::Init(PRUint32 aFlags, PRUint32 aWrapColumn,
 
   mPreLevel = 0;
 
-  mCharSet = aCharSet;
+  mCharset = aCharSet;
 
   // set up entity converter if we are going to need it
   if (mFlags & nsIDocumentEncoder::OutputEncodeW3CEntities) {
@@ -496,7 +496,7 @@ nsHTMLContentSerializer::EscapeURI(const nsAString& aURI, nsAString& aEscapedURI
   nsresult rv = NS_OK;
 
 
-  if (!mCharSet.IsEmpty() && !IsASCII(uri)) {
+  if (!mCharset.IsEmpty() && !IsASCII(uri)) {
     textToSubURI = do_GetService(NS_ITEXTTOSUBURI_CONTRACTID, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
   }
@@ -511,7 +511,7 @@ nsHTMLContentSerializer::EscapeURI(const nsAString& aURI, nsAString& aEscapedURI
   while ((end = uri.FindCharInSet("%#;/?:@&=+$,", start)) != -1) {
     part = Substring(aURI, start, (end-start));
     if (textToSubURI && !IsASCII(part)) {
-      rv = textToSubURI->ConvertAndEscape(mCharSet.get(), part.get(), getter_Copies(escapedURI));
+      rv = textToSubURI->ConvertAndEscape(mCharset.get(), part.get(), getter_Copies(escapedURI));
       NS_ENSURE_SUCCESS(rv, rv);
     }
     else {
@@ -529,7 +529,7 @@ nsHTMLContentSerializer::EscapeURI(const nsAString& aURI, nsAString& aEscapedURI
     // Escape the remaining part.
     part = Substring(aURI, start, aURI.Length()-start);
     if (textToSubURI) {
-      rv = textToSubURI->ConvertAndEscape(mCharSet.get(), part.get(), getter_Copies(escapedURI));
+      rv = textToSubURI->ConvertAndEscape(mCharset.get(), part.get(), getter_Copies(escapedURI));
       NS_ENSURE_SUCCESS(rv, rv);
     }
     else {

content/base/src/nsHTMLContentSerializer.h

@@ -160,9 +160,7 @@ class nsHTMLContentSerializer : public nsXMLContentSerializer {
   PRInt32   mMaxColumn;
   nsString  mLineBreak;
 
-  nsCString mCharSet;
-
- // To keep track of startvalue of OL and first list item for nested lists
+  // To keep track of startvalue of OL and first list item for nested lists
   struct olState {
     olState(PRInt32 aStart, PRBool aIsFirst):startVal(aStart),isFirstListItem(aIsFirst)
     {

content/base/src/nsXMLContentSerializer.cpp

@@ -96,6 +96,7 @@ NS_IMETHODIMP
 nsXMLContentSerializer::Init(PRUint32 flags, PRUint32 aWrapColumn,
                              const char* aCharSet, PRBool aIsCopying)
 {
+  mCharset = aCharSet;
   return NS_OK;
 }
 
@@ -1002,9 +1003,17 @@ nsXMLContentSerializer::AppendDocumentStart(nsIDOMDocument *aDocument,
 
   aStr += NS_LITERAL_STRING("<?xml version=\"") + version + endQuote;
   
-  if (!encoding.IsEmpty()) {
-    aStr += NS_LITERAL_STRING(" encoding=\"") + encoding + endQuote;
+  if (!mCharset.IsEmpty()) {
+    aStr += NS_LITERAL_STRING(" encoding=\"") +
+      NS_ConvertASCIItoUTF16(mCharset) + endQuote;
   }
+  // Otherwise just don't output an encoding attr.  Not that we expect
+  // mCharset to ever be empty.
+#ifdef DEBUG
+  else {
+    NS_WARNING("Empty mCharset?  How come?");
+  }
+#endif
 
   if (!standalone.IsEmpty()) {
     aStr += NS_LITERAL_STRING(" standalone=\"") + standalone + endQuote;

content/base/src/nsXMLContentSerializer.h

@@ -153,6 +153,10 @@ class nsXMLContentSerializer : public nsIContentSerializer {
 
   PRInt32 mPrefixIndex;
   nsVoidArray mNameSpaceStack;
+
+  // The charset that was passed to Init()
+  nsCString mCharset;
+  
   PRPackedBool mInAttribute;
   PRPackedBool mAddNewline;
 };