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

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 1d2b9cbccd43d9ae27d103c2176ef162dc3c3e74..6312898adc5291db99a4e7c4c67c393fbf0e5351 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -5282,6 +5282,12 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_SYNC_TABS_DESCRIPTION" desc="Description for the flag to enable syncing the open tabs datatype">
         Enable open tabs in the sync settings. This allows syncing your open tabs to other clients.
       </message>
+      <message name="IDS_FLAGS_SYNC_TAB_FAVICONS_NAME" desc="Title for the flag to enable syncing tab favicons with tab sync">
+        Enable tab favicon sync.
+      </message>
+      <message name="IDS_FLAGS_SYNC_TAB_FAVICONS_DESCRIPTION" desc="Description for the flag to enable syncing tab favicons with tab sync">
+        Enable syncing the favicons of open tabs as part of Open Tab sync.
+      </message>
       <message name="IDS_FLAGS_SYNC_APP_NOTIFICATIONS_NAME" desc="Title for the flag to disable syncing the app notifications datatype">
         Disable syncing app notifications
       </message>