DevTools: notify backend agents about profiler started/stopped events

Source/core/inspector/InspectorBaseAgent.h

Index: Source/core/inspector/InspectorBaseAgent.h
diff --git a/Source/core/inspector/InspectorBaseAgent.h b/Source/core/inspector/InspectorBaseAgent.h
index eae8210979a35633618be2aa14522043f1123730..1d9b5b3d609442194c6922bd90b779c72dd41858 100644
--- a/Source/core/inspector/InspectorBaseAgent.h
+++ b/Source/core/inspector/InspectorBaseAgent.h
@@ -56,6 +56,9 @@ public:
     virtual void discardAgent() { }
     virtual void didCommitLoadForMainFrame() { }
     virtual void flushPendingFrontendMessages() { }
+    virtual void profilerStarted() { }
+    virtual void profilerStopped() { }
+
 
     String name() { return m_name; }
     void appended(InstrumentingAgents*, InspectorState*);
@@ -79,6 +82,8 @@ public:
     void registerInDispatcher(InspectorBackendDispatcher*);
     void discardAgents();
     void flushPendingFrontendMessages();
+    void profilerStarted();
+    void profilerStopped();
 
 private:
     InstrumentingAgents* m_instrumentingAgents;