Extract ProcessManager from ExtensionSystem.

chrome/browser/extensions/devtools_util.cc

 // Copyright 2013 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/devtools_util.h"
 
 #include "chrome/browser/devtools/devtools_window.h"
 #include "chrome/browser/profiles/profile.h"
 #include "extensions/browser/extension_host.h"
 #include "extensions/browser/extension_system.h"
@@ skipping 10 matching lines @@
 void InspectExtensionHost(ExtensionHost* host) {
   if (host)
     DevToolsWindow::OpenDevToolsWindow(host->host_contents());
 }
 
 }  // namespace
 
 void InspectBackgroundPage(const Extension* extension, Profile* profile) {
   DCHECK(extension);
   ExtensionSystem* system = ExtensionSystem::Get(profile);
-  ExtensionHost* host =
-      system->process_manager()->GetBackgroundHostForExtension(extension->id());
+  ExtensionHost* host = ProcessManager::Get(profile)
+                            ->GetBackgroundHostForExtension(extension->id());
   if (host) {
     InspectExtensionHost(host);
   } else {
     system->lazy_background_task_queue()->AddPendingTask(
         profile,
         extension->id(),
         base::Bind(&InspectExtensionHost));
   }
 }
 
 }  // namespace devtools_util
 }  // namespace extensions