Prevent crash on unrecoverable error method call on FrontendDataTypeControllers.

chrome/browser/sync/profile_sync_service.h

 // Copyright (c) 2011 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_SYNC_PROFILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_
 #pragma once
 
 #include <list>
 #include <string>
@@ skipping 85 matching lines @@
 //      datatype, propagating such changes into and out of the sync backend
 //      as necessary.
 //
 //      When a datatype is in the process of becoming active, it may be
 //      in some intermediate state.  Those finer-grained intermediate states
 //      are differentiated by the DataTypeController state.
 //
 class ProfileSyncService : public browser_sync::SyncFrontend,
                            public browser_sync::SyncPrefObserver,
                            public browser_sync::UnrecoverableErrorHandler,
-                           public content::NotificationObserver {
+                           public content::NotificationObserver,
+                           // TODO(lipalani): crbug.com/100829. Instead of
+                           // doing this vend weak pointers from a factory.
+                           public base::SupportsWeakPtr<ProfileSyncService> {
+
  public:
   typedef ProfileSyncServiceObserver Observer;
   typedef browser_sync::SyncBackendHost::Status Status;
 
   enum SyncEventCodes  {
     MIN_SYNC_EVENT_CODE = 0,
 
     // Events starting the sync service.
     START_FROM_NTP = 1,      // Sync was started from the ad in NTP
     START_FROM_WRENCH = 2,   // Sync was started from the Wrench menu.
@@ skipping 573 matching lines @@
   FailedDatatypesHandler failed_datatypes_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncService);
 };
 
 bool ShouldShowActionOnUI(
     const browser_sync::SyncProtocolError& error);
 
 
 #endif  // CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_