content: convert user action notification to observer usage

chrome/browser/ui/webui/user_actions/user_actions_ui_handler.h

Index: chrome/browser/ui/webui/user_actions/user_actions_ui_handler.h
diff --git a/chrome/browser/ui/webui/user_actions/user_actions_ui_handler.h b/chrome/browser/ui/webui/user_actions/user_actions_ui_handler.h
index de145ea6e5770272670a3e3063edcc2741639351..6ac5c143a05a3d620234ae3c3609abe252878eff 100644
--- a/chrome/browser/ui/webui/user_actions/user_actions_ui_handler.h
+++ b/chrome/browser/ui/webui/user_actions/user_actions_ui_handler.h
@@ -5,33 +5,26 @@
 #ifndef CHROME_BROWSER_UI_WEBUI_USER_ACTIONS_USER_ACTIONS_UI_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_USER_ACTIONS_USER_ACTIONS_UI_HANDLER_H_
 
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 // UI Handler for chrome://user-actions/
 // It listens to user action notifications and passes those notifications
 // into the Javascript to update the page.
-class UserActionsUIHandler : public content::NotificationObserver,
+class UserActionsUIHandler : public content::UserMetricsObserver,
                              public content::WebUIMessageHandler {
  public:
   UserActionsUIHandler();
   virtual ~UserActionsUIHandler();
 
-  // NotificationObserver implementation:
-  // Listens for user action notifications and passes the message to
-  // observeUserAction in user_actions.js.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // content::UserMetricsObserver implementation:
+  virtual void UserAction(const std::string& action) OVERRIDE;
 
   // WebUIMessageHandler implementation:
   // Does nothing for now.
   virtual void RegisterMessages() OVERRIDE;
 
  private:
-  content::NotificationRegistrar registrar_;
-
   DISALLOW_COPY_AND_ASSIGN(UserActionsUIHandler);
 };