Add context to gfx::Screen calls in support of simultaneous desktop+ash

chrome/browser/ui/ash/ash_util.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 "chrome/browser/ui/ash/ash_util.h"
 
 #include "ash/shell.h"
 #include "chrome/browser/ui/ash/ash_init.h"
 #include "ui/aura/root_window.h"
+#include "ui/gfx/screen.h"
 
 namespace chrome {
 
 bool IsNativeViewInAsh(gfx::NativeView native_view) {
 #if defined(OS_CHROMEOS)
   // Optimization. There is only ash on ChromeOS.
   return true;
 #endif
 
   if (!ash::Shell::HasInstance())
     return false;
 
   ash::Shell::RootWindowList root_windows =
       ash::Shell::GetInstance()->GetAllRootWindows();
 
   for (ash::Shell::RootWindowList::const_iterator it = root_windows.begin();
        it != root_windows.end(); ++it) {
     if ((*it)->Contains(native_view))
       return true;
   }
 
   return false;
 }
 
 bool IsNativeWindowInAsh(gfx::NativeWindow native_window) {
   return IsNativeViewInAsh(native_window);
 }
 
 void ToggleAshDesktop() {
+  gfx::Screen::ForceScreenTypeOverride(gfx::SCREEN_TYPE_ALTERNATE);
   if (!ash::Shell::HasInstance())
     OpenAsh();
   else
     CloseAsh();
+  gfx::Screen::ForceScreenTypeOverride(gfx::SCREEN_TYPE_COUNT);
 }
 
 }  // namespace chrome