[Sync] Add support for automatic enabling of syncing tab favicons.

chrome/browser/about_flags.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/about_flags.h"
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 #include <set>
@@ skipping 333 matching lines @@
     SINGLE_VALUE_TYPE(switches::kShowAutofillTypePredictions)
   },
   {
     "sync-tabs",
     IDS_FLAGS_SYNC_TABS_NAME,
     IDS_FLAGS_SYNC_TABS_DESCRIPTION,
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kEnableSyncTabs)
   },
   {
+    "sync-tab-favicons",
+    IDS_FLAGS_SYNC_TAB_FAVICONS_NAME,
+    IDS_FLAGS_SYNC_TAB_FAVICONS_DESCRIPTION,
+    kOsAll,
+    SINGLE_VALUE_TYPE(switches::kSyncTabFavicons)
+  },
+  {
     "sync-app-notifications",
     IDS_FLAGS_SYNC_APP_NOTIFICATIONS_NAME,
     IDS_FLAGS_SYNC_APP_NOTIFICATIONS_DESCRIPTION,
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kDisableSyncAppNotifications)
   },
   {
     "enable-smooth-scrolling",  // FLAGS:RECORD_UMA
     IDS_FLAGS_ENABLE_SMOOTH_SCROLLING_NAME,
     IDS_FLAGS_ENABLE_SMOOTH_SCROLLING_DESCRIPTION,
@@ skipping 721 matching lines @@
 }
 
 const Experiment* GetExperiments(size_t* count) {
   *count = num_experiments;
   return experiments;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags