Allow extension APIs to be compiled out.

chrome/browser/extensions/extension_service.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/extension_service.h"
 
 #include <algorithm>
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 517 matching lines @@
   // Idempotent, so although there is a possible race if the import
   // process finished sometime in the middle of ProfileImpl::InitExtensions,
   // it cannot happen twice.
   InitEventRouters();
 }
 
 void ExtensionService::InitEventRouters() {
   if (event_routers_initialized_)
     return;
 
+#if defined(ENABLE_EXTENSIONS)
   downloads_event_router_.reset(new ExtensionDownloadsEventRouter(profile_));
   history_event_router_.reset(new HistoryExtensionEventRouter());
   history_event_router_->ObserveProfile(profile_);
   browser_event_router_.reset(new ExtensionBrowserEventRouter(profile_));
   browser_event_router_->Init();
   preference_event_router_.reset(new ExtensionPreferenceEventRouter(profile_));
   bookmark_event_router_.reset(new BookmarkExtensionEventRouter(
       profile_->GetBookmarkModel()));
   bookmark_event_router_->Init();
   cookies_event_router_.reset(new ExtensionCookiesEventRouter(profile_));
@@ skipping 19 matching lines @@
       new chromeos::ExtensionInputMethodEventRouter);
 
   ExtensionMediaPlayerEventRouter::GetInstance()->Init(profile_);
   ExtensionInputImeEventRouter::GetInstance()->Init();
 #endif
 
 #if defined(OS_CHROMEOS) && defined(USE_VIRTUAL_KEYBOARD)
   ExtensionInputUiEventRouter::GetInstance()->Init();
 #endif
 
+#endif  // defined(ENABLE_EXTENSIONS)
   event_routers_initialized_ = true;
 }
 
 const Extension* ExtensionService::GetExtensionById(
     const std::string& id, bool include_disabled) const {
   return GetExtensionByIdInternal(id, true, include_disabled, false);
 }
 
 void ExtensionService::Init() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
@@ skipping 2050 matching lines @@
   // To coexist with certain unit tests that don't have an IO thread message
   // loop available at ExtensionService shutdown, we lazy-initialize this
   // object so that those cases neither create nor destroy an
   // APIResourceController.
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   if (!api_resource_controller_) {
     api_resource_controller_ = new extensions::APIResourceController();
   }
   return api_resource_controller_;
 }