Extract ProcessManager from ExtensionSystem.

extensions/browser/mojo/keep_alive_impl.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/mojo/keep_alive_impl.h"
 
-#include "extensions/browser/extension_system.h"
 #include "extensions/browser/process_manager.h"
 
 namespace extensions {
 
 // static
 void KeepAliveImpl::Create(content::BrowserContext* context,
                            const Extension* extension,
                            mojo::InterfaceRequest<KeepAlive> request) {
   mojo::BindToRequest(new KeepAliveImpl(context, extension), &request);
 }
 
 KeepAliveImpl::KeepAliveImpl(content::BrowserContext* context,
                              const Extension* extension)
     : context_(context), extension_(extension) {
-  ExtensionSystem* system = ExtensionSystem::Get(context_);
-  if (!system)
-    return;
-  system->process_manager()->IncrementLazyKeepaliveCount(extension_);
+  ProcessManager::Get(context_)->IncrementLazyKeepaliveCount(extension_);
 }
 
 KeepAliveImpl::~KeepAliveImpl() {
-  ExtensionSystem* system = ExtensionSystem::Get(context_);
-  if (!system)
-    return;
-  system->process_manager()->DecrementLazyKeepaliveCount(extension_);
+  ProcessManager::Get(context_)->DecrementLazyKeepaliveCount(extension_);
 }
 
 }  // namespace extensions