Revert 149869 because it broke ash_unittests on win_aura and linux_chromeos.

ash/wm/root_window_layout_manager.h

Index: ash/wm/root_window_layout_manager.h
===================================================================
--- ash/wm/root_window_layout_manager.h	(revision 149877)
+++ ash/wm/root_window_layout_manager.h	(working copy)
@@ -5,7 +5,6 @@
 #ifndef ASH_WM_ROOT_WINDOW_LAYOUT_MANAGER_H_
 #define ASH_WM_ROOT_WINDOW_LAYOUT_MANAGER_H_
 
-#include "ash/shell_window_ids.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
@@ -34,6 +33,18 @@
   explicit RootWindowLayoutManager(aura::Window* owner);
   virtual ~RootWindowLayoutManager();
 
+  views::Widget* background_widget() { return background_widget_; }
+  ui::Layer* background_layer() { return background_layer_.get(); }
+
+  // Sets the background to |widget|. Closes and destroys the old widget if it
+  // exists and differs from the new widget.
+  void SetBackgroundWidget(views::Widget* widget);
+
+  // Sets a background layer, taking ownership of |layer|.  This is provided as
+  // a lightweight alternative to SetBackgroundWidget(); layers can be simple
+  // colored quads instead of being textured.
+  void SetBackgroundLayer(ui::Layer* layer);
+
   // Overridden from aura::LayoutManager:
   virtual void OnWindowResized() OVERRIDE;
   virtual void OnWindowAddedToLayout(aura::Window* child) OVERRIDE;
@@ -47,6 +58,10 @@
  private:
   aura::Window* owner_;
 
+  // May be NULL if we're not painting a background.
+  views::Widget* background_widget_;
+  scoped_ptr<ui::Layer> background_layer_;
+
   DISALLOW_COPY_AND_ASSIGN(RootWindowLayoutManager);
 };