Modified components ui to address concern of all the time disabled check update button.

chrome/browser/ui/webui/components_ui.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_COMPONENTS_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_COMPONENTS_UI_H_
 
+#include "chrome/browser/component_updater/component_updater_service.h"
 #include "content/public/browser/web_ui_controller.h"
 #include "ui/base/layout.h"
 
 namespace base {
 class RefCountedMemory;
 }
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
-class ComponentsUI : public content::WebUIController {
+class ComponentsUI : public content::WebUIController,
+                     public component_updater::ServiceObserver {
  public:
   explicit ComponentsUI(content::WebUI* web_ui);
 
   static void OnDemandUpdate(const std::string& component_id);
 
   static base::RefCountedMemory* GetFaviconResourceBytes(
       ui::ScaleFactor scale_factor);
 
+  // Override from ServiceObserver
+  virtual void OnEvent(Events event, const std::string& id) OVERRIDE;
+
  private:
+  void ComponentEventToString(Events event, std::string* converted_event);
   DISALLOW_COPY_AND_ASSIGN(ComponentsUI);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_COMPONENTS_UI_H_