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

extensions/browser/extension_host.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 "extensions/browser/extension_host.h"
 
 #include <list>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 324 matching lines @@
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void ExtensionHost::OnRequest(const ExtensionHostMsg_Request_Params& params) {
   extension_function_dispatcher_.Dispatch(params, render_view_host());
 }
 
 void ExtensionHost::OnEventAck() {
-  EventRouter* router = ExtensionSystem::Get(browser_context_)->event_router();
+  EventRouter* router = EventRouter::Get(browser_context_);
   if (router)
     router->OnEventAck(browser_context_, extension_id());
 }
 
 void ExtensionHost::OnIncrementLazyKeepaliveCount() {
   ProcessManager* pm = ExtensionSystem::Get(
       browser_context_)->process_manager();
   if (pm)
     pm->IncrementLazyKeepaliveCount(extension());
 }
@@ skipping 65 matching lines @@
 
 void ExtensionHost::RequestMediaAccessPermission(
     content::WebContents* web_contents,
     const content::MediaStreamRequest& request,
     const content::MediaResponseCallback& callback) {
   delegate_->ProcessMediaAccessRequest(
       web_contents, request, callback, extension());
 }
 
 }  // namespace extensions