Enable sync for the settings from the Extension Settings API.

chrome/browser/extensions/extension_service.cc

Index: chrome/browser/extensions/extension_service.cc
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index dc4d403fdcc1b66339a973c7eeefc9a547942a91..3fcd6f1196ac0c4b427fc30a11dbd69a9dea677f 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -579,14 +579,12 @@ ExtensionService::ExtensionService(Profile* profile,
                                    const CommandLine* command_line,
                                    const FilePath& install_directory,
                                    ExtensionPrefs* extension_prefs,
-                                   ExtensionSettings* extension_settings,
                                    bool autoupdate_enabled,
                                    bool extensions_enabled)
     : weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
       method_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
       profile_(profile),
       extension_prefs_(extension_prefs),
-      extension_settings_(extension_settings),
       pending_extension_manager_(*ALLOW_THIS_IN_INITIALIZER_LIST(this)),
       install_directory_(install_directory),
       extensions_enabled_(extensions_enabled),
@@ -634,6 +632,12 @@ ExtensionService::ExtensionService(Profile* profile,
       new ExtensionServiceBackend(weak_ptr_factory_.GetWeakPtr(),
                                   install_directory_);
 
+  // Construct the settings on the UI thread, but all further interaction
+  // (including destruction) must be done on the FILE thread.
+  extension_settings_ =
+      new ExtensionSettings(
+          profile_->GetPath().AppendASCII(kSettingsDirectoryName));
+
   if (extensions_enabled_) {
     ExternalExtensionProviderImpl::CreateExternalProviders(
         this, profile_, &external_extension_providers_);
@@ -688,6 +692,9 @@ ExtensionService::~ExtensionService() {
     ExternalExtensionProviderInterface* provider = i->get();
     provider->ServiceShutdown();
   }
+
+  BrowserThread::DeleteSoon(
+      BrowserThread::FILE, FROM_HERE, extension_settings_);
 }
 
 void ExtensionService::InitEventRoutersAfterImport() {