Add GYP flag to optionally enable the Hangout Services extension in

chrome/browser/extensions/component_loader.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/extensions/component_loader.h"
 
 #include <map>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 271 matching lines @@
     Add(IDR_FILEMANAGER_MANIFEST, filemgr_extension_path);
     return;
   }
 #endif  // NDEBUG
   Add(IDR_FILEMANAGER_MANIFEST,
       base::FilePath(FILE_PATH_LITERAL("file_manager")));
 #endif  // defined(OS_CHROMEOS)
 }
 
 void ComponentLoader::AddHangoutServicesExtension() {
-#if defined(GOOGLE_CHROME_BUILD)
+#if defined(GOOGLE_CHROME_BUILD) || defined(ENABLE_HANGOUT_SERVICES_EXTENSION)
   Add(IDR_HANGOUT_SERVICES_MANIFEST,
       base::FilePath(FILE_PATH_LITERAL("hangout_services")));
 #endif
 }
 
 void ComponentLoader::AddHotwordHelperExtension() {
   Profile* profile = static_cast<Profile*>(browser_context_);
   if (HotwordServiceFactory::IsHotwordAllowed(profile)) {
     Add(IDR_HOTWORD_HELPER_MANIFEST,
         base::FilePath(FILE_PATH_LITERAL("hotword_helper")));
@@ skipping 309 matching lines @@
         off_the_record_context, Extension::GetBaseURLFromExtensionId(id));
     fileapi::FileSystemContext* file_system_context =
         content::BrowserContext::GetStoragePartitionForSite(
             off_the_record_context, site)->GetFileSystemContext();
     file_system_context->EnableTemporaryFileSystemInIncognito();
   }
 #endif
 }
 
 }  // namespace extensions