Add UMA histogram data representing the Synced Notifications feature.

chrome/browser/notifications/sync_notifier/chrome_notifier_delegate.h

 // Copyright (c) 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_NOTIFICATIONS_SYNC_NOTIFIER_CHROME_NOTIFIER_DELEGATE_H_
 #define CHROME_BROWSER_NOTIFICATIONS_SYNC_NOTIFIER_CHROME_NOTIFIER_DELEGATE_H_
 
+#include <map>
 #include <string>
 
 #include "chrome/browser/notifications/notification_delegate.h"
 #include "url/gurl.h"
 
 namespace notifier {
 
+enum SyncedNotificationActionType {
+  SYNCED_NOTIFICATION_ACTION_UNKNOWN,
+  SYNCED_NOTIFICATION_ACTION_CLICK,
+  SYNCED_NOTIFICATION_ACTION_BUTTON_CLICK,
+  SYNCED_NOTIFICATION_ACTION_CLOSE_BY_USER,
+  SYNCED_NOTIFICATION_ACTION_CLOSE_BY_SYSTEM,
+  SYNCED_NOTIFICATION_ACTION_TOAST_TIMEOUT,
+  // NOTE: Add new action types only immediately above this line. Also,
+  // make sure the enum list in tools/histogram/histograms.xml is
+  // updated with any change in here.
+  SYNCED_NOTIFICATION_ACTION_COUNT
+};
+
 class ChromeNotifierService;
 
 // ChromeNotifierDelegate is a NotificationDelegate which catches
 // responses from the NotificationUIManager when a notification
 // has been closed.
 
 class ChromeNotifierDelegate : public NotificationDelegate {
  public:
   // We use an id instead of a notification so we can check to see if the
   // notification still exists before acting on it instead of using a ref count.
   explicit ChromeNotifierDelegate(const std::string& notification_id,
                                   ChromeNotifierService* notifier);
 
   // NotificationDelegate interface.
   virtual void Display() OVERRIDE {}
   virtual void Error() OVERRIDE {}
   virtual void Close(bool by_user) OVERRIDE;
   virtual void Click() OVERRIDE;
   virtual void ButtonClick(int button_index) OVERRIDE;
   virtual std::string id() const OVERRIDE;
 
   virtual content::RenderViewHost* GetRenderViewHost() const OVERRIDE;
 
+  void CollectAction(SyncedNotificationActionType type);
+
  private:
   virtual ~ChromeNotifierDelegate();
   void NavigateToUrl(const GURL& destination) const;
 
   const std::string notification_id_;
   ChromeNotifierService* const chrome_notifier_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeNotifierDelegate);
 };
 
 }  // namespace notifier
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_SYNC_NOTIFIER_CHROME_NOTIFIER_DELEGATE_H_