Bug 560503. Don't check for mutation observer uniqueness; callers should handle that. r=sicking

content/base/public/nsIDocument.h

@@ -670,7 +670,8 @@ public:
   /**
    * Add a new observer of document change notifications. Whenever
    * content is changed, appended, inserted or removed the observers are
-   * informed.
+   * informed.  An observer that is already observing the document must
+   * not be added without being removed first.
    */
   virtual void AddObserver(nsIDocumentObserver* aObserver) = 0;
 

content/base/public/nsINode.h

@@ -704,14 +704,43 @@ public:
    * observer, which means that it is the responsibility of the observer to
    * remove itself in case it dies before the node.  If an observer is added
    * while observers are being notified, it may also be notified.  In general,
-   * adding observers while inside a notification is not a good idea.
+   * adding observers while inside a notification is not a good idea.  An
+   * observer that is already observing the node must not be added without
+   * being removed first.
    */
-  virtual void AddMutationObserver(nsIMutationObserver* aMutationObserver);
+  void AddMutationObserver(nsIMutationObserver* aMutationObserver)
+  {
+    nsSlots* slots = GetSlots();
+    if (slots) {
+      NS_ASSERTION(slots->mMutationObservers.IndexOf(aMutationObserver) ==
+                   nsTArray_base::NoIndex,
+                   "Observer already in the list");
+      slots->mMutationObservers.AppendElement(aMutationObserver);
+    }
+  }
+
+  /**
+   * Same as above, but only adds the observer if its not observing
+   * the node already.
+   */
+  void AddMutationObserverUnlessExists(nsIMutationObserver* aMutationObserver)
+  {
+    nsSlots* slots = GetSlots();
+    if (slots) {
+      slots->mMutationObservers.AppendElementUnlessExists(aMutationObserver);
+    }
+  }
 
   /**
    * Removes a mutation observer.
    */
-  virtual void RemoveMutationObserver(nsIMutationObserver* aMutationObserver);
+  void RemoveMutationObserver(nsIMutationObserver* aMutationObserver)
+  {
+    nsSlots* slots = GetExistingSlots();
+    if (slots) {
+      slots->mMutationObservers.RemoveElement(aMutationObserver);
+    }
+  }
 
   /**
    * Clones this node. This needs to be overriden by all node classes. aNodeInfo

content/base/src/nsDocument.cpp

@@ -3770,8 +3770,9 @@ nsDocument::ScriptLoader()
 void
 nsDocument::AddObserver(nsIDocumentObserver* aObserver)
 {
-  // The array makes sure the observer isn't already in the list
-  mObservers.AppendElementUnlessExists(aObserver);
+  NS_ASSERTION(mObservers.IndexOf(aObserver) == nsTArray_base::NoIndex,
+               "Observer already in the list");
+  mObservers.AppendElement(aObserver);
   AddMutationObserver(aObserver);
 }
 

content/base/src/nsGenericElement.cpp

@@ -283,24 +283,6 @@ nsINode::CreateSlots()
   return new nsSlots(mFlagsOrSlots);
 }
 
-void
-nsINode::AddMutationObserver(nsIMutationObserver* aMutationObserver)
-{
-  nsSlots* slots = GetSlots();
-  if (slots) {
-    slots->mMutationObservers.AppendElementUnlessExists(aMutationObserver);
-  }
-}
-
-void
-nsINode::RemoveMutationObserver(nsIMutationObserver* aMutationObserver)
-{
-  nsSlots* slots = GetExistingSlots();
-  if (slots) {
-    slots->mMutationObservers.RemoveElement(aMutationObserver);
-  }
-}
-
 PRBool
 nsINode::IsEditableInternal() const
 {

layout/svg/base/src/nsSVGOuterSVGFrame.cpp

@@ -167,10 +167,9 @@ nsSVGOuterSVGFrame::Init(nsIContent* aContent,
     if (doc->GetRootElement() == mContent) {
       mIsRootContent = PR_TRUE;
     }
-    // AddMutationObserver checks that the observer is not already added.
     // sSVGMutationObserver has the same lifetime as the document so does
     // not need to be removed
-    doc->AddMutationObserver(&sSVGMutationObserver);
+    doc->AddMutationObserverUnlessExists(&sSVGMutationObserver);
   }
 
   SuspendRedraw();  // UnsuspendRedraw is in DidReflow