With browser instant extended enabled, signing in should redirect to chrome://apps instead of to NT…

chrome/browser/ui/webui/ntp/ntp_login_handler.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/ui/webui/ntp/ntp_login_handler.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 124 matching lines @@
       prefs::kGoogleServicesUsername);
   content::WebContents* web_contents = web_ui()->GetWebContents();
   Browser* browser = chrome::FindBrowserWithWebContents(web_contents);
   if (!browser)
     return;
 
   if (username.empty()) {
 #if !defined(OS_ANDROID)
     // The user isn't signed in, show the sync promo.
     if (SyncPromoUI::ShouldShowSyncPromo(profile)) {
-      chrome::ShowBrowserSignin(browser, SyncPromoUI::SOURCE_NTP_LINK);
+      SyncPromoUI::Source source =
+          (web_contents->GetURL().spec() == chrome::kChromeUIAppsURL) ?
+              SyncPromoUI::SOURCE_APPS_PAGE_LINK : SyncPromoUI::SOURCE_NTP_LINK;
+      chrome::ShowBrowserSignin(browser, source);
       RecordInHistogram(NTP_SIGN_IN_PROMO_CLICKED);
     }
 #endif
   } else if (args->GetSize() == 4 &&
              chrome::IsCommandEnabled(browser, IDC_SHOW_AVATAR_MENU)) {
     // The user is signed in, show the profiles menu.
     double x = 0;
     double y = 0;
     double width = 0;
     double height = 0;
@@ skipping 123 matching lines @@
   values->SetString("login_status_message", message);
   values->SetString("login_status_url",
       hide_sync ? std::string() : chrome::kSyncLearnMoreURL);
   values->SetString("login_status_advanced",
       hide_sync || !error_message.empty() ? string16() :
       l10n_util::GetStringUTF16(IDS_SYNC_PROMO_NTP_BUBBLE_ADVANCED));
   values->SetString("login_status_dismiss",
       hide_sync ? string16() :
       l10n_util::GetStringUTF16(IDS_SYNC_PROMO_NTP_BUBBLE_OK));
 }