Fix the content_browsertests everywhere maybe.

ui/views/widget/desktop_aura/desktop_screen_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/views/widget/desktop_aura/desktop_screen_win.h"
 
 #include "base/logging.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/root_window_host.h"
 #include "ui/gfx/display.h"
@@ skipping 34 matching lines @@
 bool DesktopScreenWin::IsDIPEnabled() {
   return true;
 }
 
 gfx::Display DesktopScreenWin::GetDisplayMatching(
     const gfx::Rect& match_rect) const {
   return GetDisplayNearestPoint(match_rect.CenterPoint());
 }
 
 HWND DesktopScreenWin::GetHWNDFromNativeView(gfx::NativeView window) const {
-  return window->GetRootWindow()->GetAcceleratedWidget();
+  aura::RootWindow* root_window = window->GetRootWindow();
+  return root_window ? root_window->GetAcceleratedWidget() : NULL;
 }
 
 gfx::NativeWindow DesktopScreenWin::GetNativeWindowFromHWND(HWND hwnd) const {
   return (::IsWindow(hwnd)) ?
       aura::RootWindow::GetForAcceleratedWidget(hwnd) : NULL;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 gfx::Screen* CreateDesktopScreen() {
   return new DesktopScreenWin;
 }
 
 }  // namespace views