Call media query change listeners asynchronously.

Source/core/css/MediaQueryListListener.h

Index: Source/core/css/MediaQueryListListener.h
diff --git a/Source/core/css/MediaQueryListListener.h b/Source/core/css/MediaQueryListListener.h
index d9299b0b3d650dd345c4febcb4dc8022ea23a282..ba2877695a1c4ee651a81a56e132d6378ff70b7a 100644
--- a/Source/core/css/MediaQueryListListener.h
+++ b/Source/core/css/MediaQueryListListener.h
@@ -22,6 +22,7 @@
 
 #include "bindings/v8/ScriptState.h"
 #include "bindings/v8/ScriptValue.h"
+#include "core/css/MediaQueryList.h"
 #include "platform/heap/Handle.h"
 #include "wtf/RefCounted.h"
 
@@ -31,7 +32,7 @@ class MediaQueryList;
 
 // See http://dev.w3.org/csswg/cssom-view/#the-mediaquerylist-interface
 // FIXME: MediaQueryListListener should be implemented using callback interface
-class MediaQueryListListener : public RefCountedWillBeGarbageCollectedFinalized<MediaQueryListListener> {
+class MediaQueryListListener : public MediaQueryList::Listener {
 public:
     static PassRefPtrWillBeRawPtr<MediaQueryListListener> create(ScriptState* scriptState, const ScriptValue& value)
     {
@@ -41,21 +42,23 @@ public:
     }
     void call();
 
-    // Used to keep the MediaQueryList alive and registered with the MediaQueryMatcher
-    // as long as the listener exists.
-    void setMediaQueryList(MediaQueryList* query) { m_query = query; }
-    void clearMediaQueryList() { m_query = nullptr; }
+    virtual void mediaQueryChanged() { call(); }
+    virtual MediaQueryListListener* isMediaQueryListListener() { return this; }
 
     bool operator==(const MediaQueryListListener& other) const { return m_function == other.m_function; }
-
-    void trace(Visitor* visitor) { visitor->trace(m_query); }
+    virtual bool equals(MediaQueryList::Listener* other)
+    {
+        MediaQueryListListener* otherListener = other->isMediaQueryListListener();

[esprehn, 2014/07/01 00:01:06]

"is" methods shouldn't return a pointer.

[cbiesinger, 2014/07/01 00:12:09]

Can I rename it "to" even without adding an assert that the type is right? Or is
the preferred approach to add "is" and "to"?

+        if (!otherListener)
+            return false;
+        return *this == *otherListener;
+    }
 
 private:
     MediaQueryListListener(ScriptState*, const ScriptValue&);
 
     RefPtr<ScriptState> m_scriptState;
     ScriptValue m_function;
-    RefPtrWillBeMember<MediaQueryList> m_query;
 };
 
 }