Fix the settings button and UMA metrics for the message center

ui/message_center/notification_delegate.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 UI_MESSAGE_CENTER_NOTIFICATION_DELEGATE_H_
 #define UI_MESSAGE_CENTER_NOTIFICATION_DELEGATE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 31 matching lines @@
   // To be called when the user clicks a button in a notification.
   virtual void ButtonClick(int button_index);
 
   // To be called when the user types a reply to a notification.
   // TODO(crbug.com/599859) Support this feature in the message center -
   // currently it is only supported on Android.
   virtual void ButtonClickWithReply(int button_index,
                                     const base::string16& reply);
 
   // To be called when the user clicks the settings button in a notification.
-  virtual void SettingsClick();
+  // Returns whether the settings click was handled by the delegate.
+  virtual bool SettingsClick();
 
   // To be called in order to detect if a settings button should be displayed.
   virtual bool ShouldDisplaySettingsButton();
 
 #if defined(TOOLKIT_VIEWS) && !defined(OS_MACOSX)
   // To be called to construct the contents view of a popup for notifications
   // whose type is NOTIFICATION_TYPE_CUSTOM.
   virtual std::unique_ptr<CustomContent> CreateCustomContent();
 #endif
 
@@ skipping 46 matching lines @@
 
  private:
   ButtonClickCallback button_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(HandleNotificationButtonClickDelegate);
 };
 
 }  //  namespace message_center
 
 #endif  // UI_MESSAGE_CENTER_NOTIFICATION_DELEGATE_H_