Makes construction of (ash)RemoteWindowTreeHostWin explicit

chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc

Index: chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc
diff --git a/chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc b/chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc
index 374f300b99498080279a972ae5d2cf41315a67ce..277a5aa01105843f915992a8da2eae40feb21e6e 100644
--- a/chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc
+++ b/chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc
@@ -120,14 +120,10 @@ void ChromeMetroViewerProcessHost::OnSetTargetSurface(
     float device_scale) {
   HWND hwnd = reinterpret_cast<HWND>(target_surface);
 
-  // Make hwnd available as early as possible for proper InputMethod
-  // initialization.
-  ash::AshRemoteWindowTreeHostWin::Init();
-  aura::RemoteWindowTreeHostWin::Instance()->
-      InitializeRemoteWindowAndScaleFactor(hwnd, device_scale);
-
-  // Now start the Ash shell environment.
-  chrome::OpenAsh();
+  gfx::InitDeviceScaleFactor(device_scale);
+  chrome::OpenAsh(hwnd);
+  DCHECK(aura::RemoteWindowTreeHostWin::Instance());
+  DCHECK_EQ(hwnd, aura::RemoteWindowTreeHostWin::Instance()->remote_window());
   ash::Shell::GetInstance()->CreateShelf();
   ash::Shell::GetInstance()->ShowShelf();