[Sync] Refactor non-frontend DTC to handle new API properly.

chrome/browser/sync/api/syncable_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_API_SYNCABLE_SERVICE_H_
 #define CHROME_BROWSER_SYNC_API_SYNCABLE_SERVICE_H_
 #pragma once
 
 #include <vector>
 
 #include "base/compiler_specific.h"
+#include "base/memory/weak_ptr.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 #include "chrome/browser/sync/api/sync_change_processor.h"
 #include "chrome/browser/sync/api/sync_data.h"
 #include "chrome/browser/sync/api/sync_error.h"
 
 class SyncData;
 
 typedef std::vector<SyncData> SyncDataList;
 
-class SyncableService : public SyncChangeProcessor {
+// TODO(zea): remove SupportsWeakPtr in favor of having all SyncableService
+// implementers provide a way of getting a weak pointer to themselves.
+// See crbug.com/100114.
+class SyncableService : public SyncChangeProcessor,
+                        public base::SupportsWeakPtr<SyncableService> {
  public:
   // Informs the service to begin syncing the specified synced datatype |type|.
   // The service should then merge |initial_sync_data| into it's local data,
   // calling |sync_processor|'s ProcessSyncChanges as necessary to reconcile the
   // two. After this, the SyncableService's local data should match the server
   // data, and the service should be ready to receive and process any further
   // SyncChange's as they occur.
   // Returns: A default SyncError (IsSet() == false) if no errors were
   //          encountered, and a filled SyncError (IsSet() == true)
   //          otherwise.
@@ skipping 17 matching lines @@
   //          otherwise.
   virtual SyncError ProcessSyncChanges(
       const tracked_objects::Location& from_here,
       const SyncChangeList& change_list) OVERRIDE = 0;
 
  protected:
   virtual ~SyncableService();
 };
 
 #endif  // CHROME_BROWSER_SYNC_API_SYNCABLE_SERVICE_H_