Add a mechanism to let TracingController invoke JavaScript via TracingUI

content/public/browser/tracing_controller.h

Index: content/public/browser/tracing_controller.h
diff --git a/content/public/browser/tracing_controller.h b/content/public/browser/tracing_controller.h
index 68184a5a844deaa2cb752643ccfb6a1e57fe011d..0dce8562a08fd8188b7968486f442eaad0042268 100644
--- a/content/public/browser/tracing_controller.h
+++ b/content/public/browser/tracing_controller.h
@@ -18,6 +18,7 @@ class FilePath;
 namespace content {
 
 class TracingController;
+class TracingUI;
 
 // TracingController is used on the browser processes to enable/disable
 // trace status and collect trace data. Only the browser UI thread is allowed
@@ -161,6 +162,10 @@ class TracingController {
   // watch event callback.
   virtual bool CancelWatchEvent() = 0;
 
+  // Regsiter/Unregister tracing UI that is using this TracingController.

[dsinclair, 2014/01/08 15:57:27]

nit: s/Regsiter/Register

+  virtual void RegisterTracingUI(TracingUI* tracing_ui) = 0;
+  virtual void UnregisterTracingUI(TracingUI* tracing_ui) = 0;
+
  protected:
   virtual ~TracingController() {}
 };