Make the MediaQueryList listener an EventListener

Source/core/css/MediaQueryMatcher.cpp

Index: Source/core/css/MediaQueryMatcher.cpp
diff --git a/Source/core/css/MediaQueryMatcher.cpp b/Source/core/css/MediaQueryMatcher.cpp
index 12d21b0148b004e3fbec10a2b2f61028124f7164..26285a25f8688380b07e17127657b68a8ff4bbe9 100644
--- a/Source/core/css/MediaQueryMatcher.cpp
+++ b/Source/core/css/MediaQueryMatcher.cpp
@@ -23,6 +23,7 @@
 #include "core/css/MediaList.h"
 #include "core/css/MediaQueryEvaluator.h"
 #include "core/css/MediaQueryList.h"
+#include "core/css/MediaQueryListEvent.h"
 #include "core/css/MediaQueryListListener.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/Document.h"
@@ -106,8 +107,13 @@ void MediaQueryMatcher::mediaFeaturesChanged()
         return;
 
     WillBeHeapVector<RefPtrWillBeMember<MediaQueryListListener> > listenersToNotify;
-    for (MediaQueryListSet::iterator it = m_mediaLists.begin(); it != m_mediaLists.end(); ++it)
-        (*it)->mediaFeaturesChanged(&listenersToNotify);
+    for (MediaQueryListSet::iterator it = m_mediaLists.begin(); it != m_mediaLists.end(); ++it) {
+        if ((*it)->mediaFeaturesChanged(&listenersToNotify)) {
+            RefPtrWillBeRawPtr<Event> event(MediaQueryListEvent::create((*it)->media(), (*it)->matches()));
+            event->setTarget(*it);
+            m_document->enqueueUniqueAnimationFrameEvent(event);

[haraken, 2014/07/20 05:14:49]

I'm not quite sure of this. I wonder why MediaqueryListEvent wants to use
per-animation-frame events whereas other events are using
not-per-animation-frame events. Elliott would be the best reviewer on this.

[cbiesinger, 2014/07/21 22:07:19]

Yeah, hmm, I'm not sure... come to think of it, with the way I do this, you only
get the information (.matches) of the first event per a frame, so maybe this
should be changed. Elliott, any thoughts?

+        }
+    }
 
     m_document->enqueueMediaQueryChangeListeners(listenersToNotify);
 }