[Sync] Have SyncableService's take ownership of their SyncChangeProcessor.

chrome/browser/extensions/settings/syncable_settings_storage.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/extensions/settings/syncable_settings_storage.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/extensions/settings/settings_namespace.h"
 #include "chrome/browser/extensions/settings/settings_sync_util.h"
 #include "chrome/browser/sync/api/sync_data.h"
@@ skipping 122 matching lines @@
 
 SyncError SyncableSettingsStorage::StartSyncing(
     syncable::ModelType type,
     const DictionaryValue& sync_state,
     SyncChangeProcessor* sync_processor) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   DCHECK(type == syncable::EXTENSION_SETTINGS ||
          type == syncable::APP_SETTINGS);
   DCHECK_EQ(sync_type_, syncable::UNSPECIFIED);
   DCHECK(!sync_processor_);
+  DCHECK(sync_processor);
   DCHECK(synced_keys_.empty());
 
   sync_type_ = type;
   sync_processor_ = sync_processor;
 
   ReadResult maybe_settings = delegate_->Get();
   if (maybe_settings.HasError()) {
     return SyncError(
         FROM_HERE,
         std::string("Failed to get settings: ") + maybe_settings.error(),
@@ skipping 299 matching lines @@
         FROM_HERE,
         std::string("Error pushing sync remove to local settings: ") +
             result.error(),
         sync_type_);
   }
   changes->push_back(SettingChange(key, old_value, NULL));
   return SyncError();
 }
 
 }  // namespace extensions