DevTools: use per-LocalFrame instrumenting agents instead of per-Page ones.

Source/core/inspector/InspectorTimelineAgent.h

 /*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
@@ skipping 255 matching lines @@
     PassRefPtr<TypeBuilder::Timeline::TimelineEvent> createCountersUpdate();
     void clearRecordStack();
     PassRefPtr<TypeBuilder::Timeline::TimelineEvent> createRecordForEvent(const TraceEventDispatcher::TraceEvent&, const String& type, PassRefPtr<JSONObject> data);
 
     void localToPageQuad(const RenderObject& renderer, const LayoutRect&, FloatQuad*);
     long long nodeId(Node*);
     long long nodeId(RenderObject*);
 
     double timestamp();
 
-    LocalFrame* mainFrame() const;
+    LocalFrame* inspectedFrame() const;
 
     bool isStarted();
     void innerStart();
     void innerStop(bool fromConsole);
     void setLiveEvents(const String&);
 
     RawPtrWillBeMember<InspectorPageAgent> m_pageAgent;
     RawPtrWillBeMember<InspectorLayerTreeAgent> m_layerTreeAgent;
     InspectorFrontend::Timeline* m_frontend;
     InspectorClient* m_client;
@@ skipping 23 matching lines @@
     typedef WillBeHeapHashMap<ThreadIdentifier, TimelineThreadState> ThreadStateMap;
     ThreadStateMap m_threadStates;
     bool m_mayEmitFirstPaint;
     HashSet<String> m_liveEvents;
     double m_lastProgressTimestamp;
 };
 
 } // namespace blink
 
 #endif // !defined(InspectorTimelineAgent_h)