Revert of Remove remote tree host and some related input and metro_driver code

chrome/browser/browser_process_platform_part_aurawin.h

+// Copyright (c) 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.
+
+#ifndef CHROME_BROWSER_BROWSER_PROCESS_PLATFORM_PART_AURAWIN_H_
+#define CHROME_BROWSER_BROWSER_PROCESS_PLATFORM_PART_AURAWIN_H_
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/browser_process_platform_part_base.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+class ChromeMetroViewerProcessHost;
+
+class BrowserProcessPlatformPart : public BrowserProcessPlatformPartBase,
+                                   public content::NotificationObserver {
+ public:
+  BrowserProcessPlatformPart();
+  ~BrowserProcessPlatformPart() override;
+
+  // Invoked when the ASH metro viewer process on Windows 8 exits.
+  void OnMetroViewerProcessTerminated();
+
+  // Overridden from BrowserProcessPlatformPartBase:
+  void PlatformSpecificCommandLineProcessing(
+      const base::CommandLine& command_line) override;
+
+  // content::NotificationObserver method:
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
+
+ private:
+  // Hosts the channel for the Windows 8 metro viewer process which runs in
+  // the ASH environment.
+  scoped_ptr<ChromeMetroViewerProcessHost> metro_viewer_process_host_;
+
+  content::NotificationRegistrar registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrowserProcessPlatformPart);
+};
+
+#endif  // CHROME_BROWSER_BROWSER_PROCESS_PLATFORM_PART_AURAWIN_H_