Sync Promo: Add a way to collapse the sync promo

chrome/browser/ui/webui/ntp/new_tab_ui.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 "build/build_config.h"
 
 #include "chrome/browser/ui/webui/ntp/new_tab_ui.h"
 
 #include <set>
 
@@ skipping 369 matching lines @@
   if (NewTabUI::FirstRunDisabled())
     NewTabHTMLSource::set_first_run(false);
 
   static bool first_view = true;
   if (first_view) {
     first_view = false;
   }
 
   if (!GetProfile()->IsOffTheRecord()) {
     PrefService* pref_service = GetProfile()->GetPrefs();
-    AddMessageHandler((new NTPLoginHandler())->Attach(this));
+    if (!NewTabSyncSetupHandler::ShouldShowSyncPromo())
+      AddMessageHandler((new NTPLoginHandler())->Attach(this));
     AddMessageHandler((new ShownSectionsHandler(pref_service))->Attach(this));
     AddMessageHandler((new browser_sync::ForeignSessionHandler())->
         Attach(this));
     AddMessageHandler((new MostVisitedHandler())->Attach(this));
     AddMessageHandler((new RecentlyClosedTabsHandler())->Attach(this));
     AddMessageHandler((new MetricsHandler())->Attach(this));
     if (GetProfile()->IsSyncAccessible())
       AddMessageHandler((new NewTabPageSyncHandler())->Attach(this));
     ExtensionService* service = GetProfile()->GetExtensionService();
     // We might not have an ExtensionService (on ChromeOS when not logged in
@@ skipping 282 matching lines @@
   SendResponse(request_id, html_bytes);
 }
 
 std::string NewTabUI::NewTabHTMLSource::GetMimeType(const std::string&) const {
   return "text/html";
 }
 
 bool NewTabUI::NewTabHTMLSource::ShouldReplaceExistingSource() const {
   return false;
 }