CrOS: Add print statements to help debug BrowserProcessImpl::Unpin crash.

chrome/browser/notifications/profile_notification.h

 // Copyright 2014 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_PROFILE_NOTIFICATION_H_
 #define CHROME_BROWSER_NOTIFICATIONS_PROFILE_NOTIFICATION_H_
 
 #include <string>
 
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 
 class ScopedKeepAlive;
 
 // This class keeps a Notification objects and its corresponding Profile, so
 // that when the Notification UI manager needs to return or cancel all
 // notifications for a given Profile we have the ability to do this.
-class ProfileNotification {
+class ProfileNotification : public content::NotificationObserver {
  public:
   // Returns a string that uniquely identifies a profile + delegate_id pair.
   // The profile_id is used as an identifier to identify a profile instance; it
   // cannot be NULL. The ID becomes invalid when a profile is destroyed.
   static std::string GetProfileNotificationId(const std::string& delegate_id,
                                               ProfileID profile_id);
 
   ProfileNotification(Profile* profile, const Notification& notification);
-  ~ProfileNotification();
+  ~ProfileNotification() override;
 
   ProfileID profile_id() const { return profile_id_; }
   const Notification& notification() const { return notification_; }
 
+  // content::NotificationObserver:
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
+
  private:
   // Used for equality comparision in notification maps.
   ProfileID profile_id_;
 
   Notification notification_;
 
   std::unique_ptr<ScopedKeepAlive> keep_alive_;
 
+  content::NotificationRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileNotification);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_PROFILE_NOTIFICATION_H_