Add a mechanism to let TracingController invoke JavaScript via TracingUI

content/browser/tracing/tracing_ui.h

Index: content/browser/tracing/tracing_ui.h
diff --git a/content/browser/tracing/tracing_ui.h b/content/browser/tracing/tracing_ui.h
index 85bbce15c2cb427387258e532da46b7b8d65fd83..752d8be23f5b0f32c883e9d6911bafdae38b7244 100644
--- a/content/browser/tracing/tracing_ui.h
+++ b/content/browser/tracing/tracing_ui.h
@@ -13,6 +13,8 @@ namespace content {
 class TracingUI : public WebUIController {
  public:
   explicit TracingUI(WebUI* web_ui);
+  virtual ~TracingUI() OVERRIDE;
+  void OnMonitoringStateChanged(bool is_monitoring);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TracingUI);