Make browser process a singleton service

chrome/browser/ui/ash/ash_util.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_ASH_ASH_UTIL_H_
 #define CHROME_BROWSER_UI_ASH_ASH_UTIL_H_
 
+#include <memory>
+
+#include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
+
+namespace service_manager {
+class Service;
+}
+
 namespace ui {
 class Accelerator;
 }  // namespace ui
 
 namespace ash_util {
 
 // Returns the name of the ash service depending on whether the browser is
 // running in classic ash or mash.
 const char* GetAshServiceName();
 
+// Creates an in-process Service instance of which can host common ash
+// interfaces.
+std::unique_ptr<service_manager::Service> CreateEmbeddedAshService(
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
+
 }  // namespace ash_util
 
 // TODO(jamescook): Change this namespace to ash_util.
 namespace chrome {
 
 // Returns true if Ash should be run at startup.
 bool ShouldOpenAshOnStartup();
 
 // Returns true if Chrome is running in the mash shell.
 bool IsRunningInMash();
 
 // Returns true if the given |accelerator| has been deprecated and hence can
 // be consumed by web contents if needed.
 bool IsAcceleratorDeprecated(const ui::Accelerator& accelerator);
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_UI_ASH_ASH_UTIL_H_