Remove remote tree host and some related input and metro_driver code

chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.h

-// Copyright 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_METRO_VIEWER_CHROME_METRO_VIEWER_PROCESS_HOST_AURAWIN_H_
-#define CHROME_BROWSER_METRO_VIEWER_CHROME_METRO_VIEWER_PROCESS_HOST_AURAWIN_H_
-
-#include <stdint.h>
-
-#include "base/macros.h"
-#include "win8/viewer/metro_viewer_process_host.h"
-
-namespace base {
-class FilePath;
-}
-
-class ChromeMetroViewerProcessHost : public win8::MetroViewerProcessHost {
- public:
-  ChromeMetroViewerProcessHost();
-  ~ChromeMetroViewerProcessHost() override;
-
- private:
-  // win8::MetroViewerProcessHost implementation
-  void OnChannelError() override;
-
-  // IPC::Listener implementation
-  void OnChannelConnected(int32_t peer_pid) override;
-  void OnSetTargetSurface(gfx::NativeViewId target_surface,
-                          float device_scale) override;
-  void OnOpenURL(const base::string16& url) override;
-  void OnHandleSearchRequest(const base::string16& search_string) override;
-  void OnWindowSizeChanged(uint32_t width, uint32_t height) override;
-
-  DISALLOW_COPY_AND_ASSIGN(ChromeMetroViewerProcessHost);
-};
-
-#endif  // CHROME_BROWSER_METRO_VIEWER_CHROME_METRO_VIEWER_PROCESS_HOST_AURAWIN_H_