cleanup: Use EventRouter instead of ExtensionSystem::Get->event_router()

chrome/browser/extensions/api/bluetooth/bluetooth_socket_event_dispatcher.cc

 // Copyright 2014 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/api/bluetooth/bluetooth_socket_event_dispatcher.h"
 
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/api/bluetooth/bluetooth_api_socket.h"
 #include "chrome/common/extensions/api/bluetooth.h"
 #include "extensions/browser/event_router.h"
-#include "extensions/browser/extension_system.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 
 namespace {
 
 namespace bluetooth = extensions::api::bluetooth;
 using extensions::BluetoothApiSocket;
 
 int kDefaultBufferSize = 4096;
 
@@ skipping 141 matching lines @@
 void BluetoothSocketEventDispatcher::DispatchEvent(
     const std::string& extension_id,
     scoped_ptr<Event> event) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   content::BrowserContext* context =
       reinterpret_cast<content::BrowserContext*>(browser_context_id_);
   if (!extensions::ExtensionsBrowserClient::Get()->IsValidContext(context))
     return;
 
-  EventRouter* router = ExtensionSystem::Get(context)->event_router();
+  EventRouter* router = EventRouter::Get(context);
   if (router)
     router->DispatchEventToExtension(extension_id, event.Pass());
 }
 
 }  // namespace api
 }  // namespace extensions