DevTools: support configurable category filter for trace events callback

content/renderer/devtools/devtools_agent.h

Index: content/renderer/devtools/devtools_agent.h
diff --git a/content/renderer/devtools/devtools_agent.h b/content/renderer/devtools/devtools_agent.h
index 68f3bc4fc2c951358833fa9b15c1657baf5e165d..92fc477c7f53e1bcb66c31b6003bb4205fabf952 100644
--- a/content/renderer/devtools/devtools_agent.h
+++ b/content/renderer/devtools/devtools_agent.h
@@ -63,7 +63,11 @@ class DevToolsAgent : public RenderViewObserver,
       int numArgs, const char* const* argNames, const unsigned char* argTypes,
       const unsigned long long* argValues,
       unsigned char flags, double timestamp);
-  virtual void setTraceEventCallback(TraceEventCallback cb) OVERRIDE;
+  virtual void resetTraceEventCallback();
+  virtual void setTraceEventCallback(const blink::WebString& category_filter,
+                                     TraceEventCallback cb);
+  // FIXME: this overload is obsolete, drop it and add OVERRIDE to the above.
+  virtual void setTraceEventCallback(TraceEventCallback cb);
   virtual void startGPUEventsRecording() OVERRIDE;
   virtual void stopGPUEventsRecording() OVERRIDE;