Refactor preference syncing.

chrome/browser/web_resource/web_resource_service.cc

 // Copyright (c) 2011 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/web_resource/web_resource_service.h"
 
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
@@ skipping 200 matching lines @@
       in_fetch_(false),
       web_resource_server_(web_resource_server),
       apply_locale_to_url_(apply_locale_to_url),
       notification_type_(notification_type),
       last_update_time_pref_name_(last_update_time_pref_name),
       start_fetch_delay_(start_fetch_delay),
       cache_update_delay_(cache_update_delay),
       web_resource_update_scheduled_(false) {
   DCHECK(prefs);
   DCHECK(profile);
-  prefs_->RegisterStringPref(last_update_time_pref_name, "0");
+  prefs_->RegisterStringPref(last_update_time_pref_name,
+                             "0",
+                             PrefService::UNSYNCABLE_PREF);
   resource_dispatcher_host_ = g_browser_process->resource_dispatcher_host();
   web_resource_fetcher_.reset(new WebResourceFetcher(this));
 }
 
 WebResourceService::~WebResourceService() { }
 
 void WebResourceService::PostNotification(int64 delay_ms) {
   if (web_resource_update_scheduled_)
     return;
   if (delay_ms > 0) {
@@ skipping 49 matching lines @@
 }
 
 void WebResourceService::UpdateResourceCache(const std::string& json_data) {
   UnpackerClient* client = new UnpackerClient(this, json_data);
   client->Start();
 
   // Set cache update time in preferences.
   prefs_->SetString(last_update_time_pref_name_,
       base::DoubleToString(base::Time::Now().ToDoubleT()));
 }