Timeline: do not rely on UpdateLayer & PaintLayer trace events

Source/core/inspector/TimelineTraceEventProcessor.h

Index: Source/core/inspector/TimelineTraceEventProcessor.h
diff --git a/Source/core/inspector/TimelineTraceEventProcessor.h b/Source/core/inspector/TimelineTraceEventProcessor.h
index 24f9f167a1ea5e54d63885a555bc777b7facd3b3..ba1ab65df71b7cd9da2bd838828312f0e9099561 100644
--- a/Source/core/inspector/TimelineTraceEventProcessor.h
+++ b/Source/core/inspector/TimelineTraceEventProcessor.h
@@ -203,10 +203,6 @@ private:
     void registerHandler(const char* name, char, TraceEventHandler);
 
     void onBeginFrame(const TraceEvent&);
-    void onUpdateLayerBegin(const TraceEvent&);
-    void onUpdateLayerEnd(const TraceEvent&);
-    void onPaintLayerBegin(const TraceEvent&);
-    void onPaintLayerEnd(const TraceEvent&);
     void onPaintSetupBegin(const TraceEvent&);
     void onPaintSetupEnd(const TraceEvent&);
     void onRasterTaskBegin(const TraceEvent&);
@@ -237,7 +233,6 @@ private:
     ThreadStateMap m_threadStates;
 
     HashMap<unsigned long long, long long> m_layerToNodeMap;
-    unsigned long long m_layerId;
     double m_paintSetupStart;
     double m_paintSetupEnd;
     RefPtr<JSONObject> m_gpuTask;