Bug 950657. Give WebIDL callbacks an operator== that does the right thing. r=smaug

dom/bindings/CallbackObject.h

@@ -102,6 +102,15 @@ protected:
     Init(aCallbackObject->mCallback, aCallbackObject->mIncumbentGlobal);
   }
 
+  bool operator==(const CallbackObject& aOther) const
+  {
+    JSObject* thisObj =
+      js::UncheckedUnwrap(CallbackPreserveColor());
+    JSObject* otherObj =
+      js::UncheckedUnwrap(aOther.CallbackPreserveColor());
+    return thisObj == otherObj;
+  }
+
 private:
   inline void Init(JSObject* aCallback, nsIGlobalObject* aIncumbentGlobal)
   {
@@ -304,11 +313,7 @@ public:
       return false;
     }
 
-    JSObject* thisObj =
-      js::UncheckedUnwrap(GetWebIDLCallback()->CallbackPreserveColor());
-    JSObject* otherObj =
-      js::UncheckedUnwrap(aOtherCallback->CallbackPreserveColor());
-    return thisObj == otherObj;
+    return *GetWebIDLCallback() == *aOtherCallback;
   }
 
   bool operator==(XPCOMCallbackT* aOtherCallback) const

dom/bindings/Codegen.py

@@ -10726,6 +10726,12 @@ class CGCallback(CGClass):
                 realMethods.append(method)
             else:
                 realMethods.extend(self.getMethodImpls(method))
+        realMethods.append(
+            ClassMethod("operator==", "bool",
+                        [Argument("const %s&" % name, "aOther")],
+                        inline=True, bodyInHeader=True,
+                        const=True,
+                        body=("return %s::operator==(aOther);" % baseName)))
         CGClass.__init__(self, name,
                          bases=[ClassBase(baseName)],
                          constructors=self.getConstructors(),

layout/style/MediaQueryList.cpp

@@ -137,11 +137,8 @@ MediaQueryList::AddListener(MediaQueryListListener& aListener)
     RecomputeMatches();
   }
 
-  CallbackType callback(&aListener);
-
   for (uint32_t i = 0; i < mCallbacks.Length(); ++i) {
-    CallbackType thisCallback(mCallbacks[i]);
-    if (callback == thisCallback) {
+    if (aListener == *mCallbacks[i]) {
       // Already registered
       return;
     }
@@ -172,11 +169,8 @@ MediaQueryList::RemoveListener(nsIDOMMediaQueryListListener *aListener)
 void
 MediaQueryList::RemoveListener(MediaQueryListListener& aListener)
 {
-  CallbackType callback(&aListener);
-
   for (uint32_t i = 0; i < mCallbacks.Length(); ++i) {
-    CallbackType thisCallback(mCallbacks[i]);
-    if (callback == thisCallback) {
+    if (aListener == *mCallbacks[i]) {
       mCallbacks.RemoveElementAt(i);
       if (!HasListeners()) {
         // See NS_ADDREF_THIS() in AddListener.

layout/style/MediaQueryList.h

@@ -44,9 +44,6 @@ public:
 
   nsISupports* GetParentObject() const;
 
-  typedef CallbackObjectHolder<mozilla::dom::MediaQueryListListener,
-                               nsIDOMMediaQueryListListener> CallbackType;
-
   struct HandleChangeData {
     nsRefPtr<MediaQueryList> mql;
     nsCOMPtr<nsIDOMMediaQueryListListener> listener;