Add GrabWindowSnapshotAsync tests

ui/aura/remote_root_window_host_win.cc

 // 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.
 
 #include "ui/aura/remote_root_window_host_win.h"
 
 #include <windows.h>
 
 #include <algorithm>
 
@@ skipping 149 matching lines @@
     : remote_window_(NULL),
       host_(NULL),
       ignore_mouse_moves_until_set_cursor_ack_(false),
       event_flags_(0),
       window_size_(aura::WindowTreeHost::GetNativeScreenSize()) {
   prop_.reset(new ui::ViewProp(NULL, kWindowTreeHostWinKey, this));
   CreateCompositor(GetAcceleratedWidget());
 }
 
 RemoteWindowTreeHostWin::~RemoteWindowTreeHostWin() {
+  DestroyCompositor();
   g_instance = NULL;
 }
 
 void RemoteWindowTreeHostWin::Connected(IPC::Sender* host, HWND remote_window) {
   CHECK(host_ == NULL);
   host_ = host;
   remote_window_ = remote_window;
   // Recreate the compositor for the target surface represented by the
   // remote_window HWND.
   CreateCompositor(remote_window_);
@@ skipping 545 matching lines @@
 }
 
 void RemoteWindowTreeHostWin::SetEventFlags(uint32 flags) {
   if (flags == event_flags_)
     return;
   event_flags_ = flags;
   SetVirtualKeyStates(event_flags_);
 }
 
 }  // namespace aura