[Sync] Fix double tranaction acquire in favicon code

chrome/browser/sync/glue/favicon_cache.cc

 // Copyright 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.
 
 #include "chrome/browser/sync/glue/favicon_cache.h"
 
+#include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "chrome/browser/favicon/favicon_service.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 #include "sync/api/time.h"
 #include "sync/protocol/favicon_image_specifics.pb.h"
@@ skipping 460 matching lines @@
   SyncedFaviconInfo* favicon_info = GetFaviconInfo(icon_url);
   if (!favicon_info)
     return;  // We reached the in-memory limit.
   base::RefCountedString* temp_string = new base::RefCountedString();
   temp_string->data() = icon_bytes;
   favicon_info->bitmap_data[SIZE_16].bitmap_data = temp_string;
   // We assume legacy favicons are 16x16.
   favicon_info->bitmap_data[SIZE_16].pixel_size.set_width(16);
   favicon_info->bitmap_data[SIZE_16].pixel_size.set_height(16);
   UpdateFaviconVisitTime(icon_url, syncer::ProtoTimeToTime(visit_time_ms));
-  UpdateSyncState(icon_url, SYNC_BOTH, syncer::SyncChange::ACTION_ADD);
+
+  // Post a task, as this can be called while still in a transaction.
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&FaviconCache::UpdateSyncState,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 icon_url,
+                 SYNC_BOTH,
+                 syncer::SyncChange::ACTION_ADD));
 }
 
 void FaviconCache::SetLegacyDelegate(FaviconCacheObserver* observer) {
   legacy_delegate_ = observer;
 }
 
 void FaviconCache::RemoveLegacyDelegate() {
   legacy_delegate_ = NULL;
 }
 
@@ skipping 413 matching lines @@
 
 size_t FaviconCache::NumFaviconsForTest() const {
   return synced_favicons_.size();
 }
 
 size_t FaviconCache::NumTasksForTest() const {
   return page_task_map_.size();
 }
 
 }  // namespace browser_sync