Introdcue AshWindowTreeHost and move ash/chrome specific code in WTH to ash.

chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc

 // 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.
 
 #include "chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.h"
 
 #include "ash/display/display_info.h"
 #include "ash/display/display_manager.h"
+#include "ash/host/ash_remote_window_tree_host_win.h"
 #include "ash/shell.h"
 #include "ash/wm/window_positioner.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part_aurawin.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
@@ skipping 91 matching lines @@
 
   if (!content::GpuDataManager::GetInstance()->GpuAccessAllowed(NULL)) {
     DVLOG(1) << "No GPU access, attempting to restart in Desktop\n";
     chrome::AttemptRestartToDesktopMode();
   }
 }
 
 void ChromeMetroViewerProcessHost::OnSetTargetSurface(
     gfx::NativeViewId target_surface) {
   HWND hwnd = reinterpret_cast<HWND>(target_surface);
+
   // Make hwnd available as early as possible for proper InputMethod
   // initialization.
+  ash::AshRemoteWindowTreeHostWin::Init();
   aura::RemoteWindowTreeHostWin::Instance()->SetRemoteWindowHandle(hwnd);
 
   // Now start the Ash shell environment.
   chrome::OpenAsh();
   ash::Shell::GetInstance()->CreateShelf();
   ash::Shell::GetInstance()->ShowShelf();
 
   // Tell our root window host that the viewer has connected.
   aura::RemoteWindowTreeHostWin::Instance()->Connected(this);
 
@@ skipping 22 matching lines @@
 void ChromeMetroViewerProcessHost::OnWindowSizeChanged(uint32 width,
                                                        uint32 height) {
   std::vector<ash::DisplayInfo> info_list;
   info_list.push_back(ash::DisplayInfo::CreateFromSpec(
       base::StringPrintf("%dx%d*%f", width, height, gfx::GetModernUIScale())));
   ash::Shell::GetInstance()->display_manager()->OnNativeDisplaysChanged(
       info_list);
   aura::RemoteWindowTreeHostWin::Instance()->HandleWindowSizeChanged(width,
                                                                      height);
 }