rAF: Introduce FrameRequestCallbackCollection for managing rAF callbacks.

Source/core/inspector/InspectorTraceEvents.cpp

Index: Source/core/inspector/InspectorTraceEvents.cpp
diff --git a/Source/core/inspector/InspectorTraceEvents.cpp b/Source/core/inspector/InspectorTraceEvents.cpp
index 261f48465cc5982b5320b3c2ca0a34e5ea27fba2..6337aab7b4725b7b91686dee0644f8c7802001c5 100644
--- a/Source/core/inspector/InspectorTraceEvents.cpp
+++ b/Source/core/inspector/InspectorTraceEvents.cpp
@@ -426,11 +426,14 @@ PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorTimerFireEvent::data(E
     return genericTimerData(context, timerId);
 }
 
-PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorAnimationFrameEvent::data(Document* document, int callbackId)
+PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorAnimationFrameEvent::data(ExecutionContext* context, int callbackId)
 {
     RefPtr<TracedValue> value = TracedValue::create();
     value->setInteger("id", callbackId);
-    value->setString("frame", toHexString(document->frame()));
+    if (context->isDocument()) {
+        Document* document = toDocument(context);
+        value->setString("frame", toHexString(document->frame()));
+    }
     setCallStack(value.get());
     return value.release();
 }