Use WS_POPUP for ash_unittests

ui/aura/root_window_host_win.h

 // 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.
 
 #ifndef UI_AURA_ROOT_WINDOW_HOST_WIN_H_
 #define UI_AURA_ROOT_WINDOW_HOST_WIN_H_
 
 #include "base/compiler_specific.h"
 #include "ui/aura/root_window_host.h"
+#include "ui/base/ui_export.h"
 #include "ui/base/win/window_impl.h"
 
 namespace aura {
 
 class RootWindowHostWin : public RootWindowHost, public ui::WindowImpl {
  public:
   RootWindowHostWin(const gfx::Rect& bounds);
   virtual ~RootWindowHostWin();
   // RootWindowHost:
   virtual void SetDelegate(RootWindowHostDelegate* delegate) OVERRIDE;
@@ skipping 61 matching lines @@
 
   bool fullscreen_;
   bool has_capture_;
   RECT saved_window_rect_;
   DWORD saved_window_style_;
   DWORD saved_window_ex_style_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindowHostWin);
 };
 
+namespace test {
+
+// Set true to let RootWindowHostWin use a popup window
+// with no frame/title so that the window size and test's
+// expectations matches.
+AURA_EXPORT void SetUsePopupAsRootWindowForTest(bool use);
+
+}  // namespace
+
 }  // namespace aura
 
 #endif  // UI_AURA_ROOT_WINDOW_HOST_WIN_H_