ash: Display system background while loading wallpaper.

ash/root_window_controller.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 ASH_ROOT_WINDOW_CONTROLLER_H_
 #define ASH_ROOT_WINDOW_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 
 class SkBitmap;
 
 namespace aura {
 class EventFilter;
 class RootWindow;
 class Window;
 namespace shared {
 class InputMethodEventFilter;
 class RootWindowEventFilter;
 }  // namespace shared
 }  // namespace aura
 
 namespace ash {
 class ToplevelWindowEventHandler;
 namespace internal {
 
 class EventClientImpl;
 class RootWindowLayoutManager;
 class ScreenDimmer;
+class SystemBackgroundController;
 class WorkspaceController;
 
 // This class maintains the per root window state for ash. This class
 // owns the root window and other dependent objects that should be
 // deleted upon the deletion of the root window.  The RootWindowController
 // for particular root window is stored as a property and can be obtained
 // using |GetRootWindowController(aura::RootWindow*)| function.
 class RootWindowController {
  public:
   explicit RootWindowController(aura::RootWindow* root_window);
@@ skipping 10 matching lines @@
   internal::WorkspaceController* workspace_controller() {
     return workspace_controller_.get();
   }
 
   internal::ScreenDimmer* screen_dimmer() {
     return screen_dimmer_.get();
   }
 
   aura::Window* GetContainer(int container_id);
 
+  void InitLayoutManagers();
   void CreateContainers();
-  void InitLayoutManagers();
+
+  // Initializes |background_|.  |is_first_run_after_boot| determines the
+  // background's initial color.
+  void CreateSystemBackground(bool is_first_run_after_boot);
+
+  // Updates |background_| to be black after the desktop background is visible.
+  void HandleDesktopBackgroundVisible();
 
   // Deletes associated objects and clears the state, but doesn't delete
   // the root window yet. This is used to delete a secondary displays'
   // root window safely when the display disconnect signal is received,
   // which may come while we're in the nested message loop.
   void Shutdown();
 
   // Deletes all child windows and performs necessary cleanup.
   void CloseChildWindows();
 
   // Returns true if the workspace has a maximized or fullscreen window.
   bool IsInMaximizedMode() const;
 
   // Moves child windows to |dest|.
   void MoveWindowsTo(aura::RootWindow* dest);
 
  private:
   // Creates each of the special window containers that holds windows of various
   // types in the shell UI.
   void CreateContainersInRootWindow(aura::RootWindow* root_window);
 
   scoped_ptr<aura::RootWindow> root_window_;
   internal::RootWindowLayoutManager* root_window_layout_;
 
+  // A background layer that's displayed beneath all other layers.  Without
+  // this, portions of the root window that aren't covered by layers will be
+  // painted white; this can show up if e.g. it takes a long time to decode the
+  // desktop background image when displaying the login screen.
+  scoped_ptr<SystemBackgroundController> background_;
+
   // An event filter that pre-handles all key events to send them to an IME.
   scoped_ptr<internal::EventClientImpl> event_client_;
   scoped_ptr<internal::ScreenDimmer> screen_dimmer_;
   scoped_ptr<internal::WorkspaceController> workspace_controller_;
 
   // We need to own event handlers for various containers.
   scoped_ptr<ToplevelWindowEventHandler> default_container_handler_;
   scoped_ptr<ToplevelWindowEventHandler> always_on_top_container_handler_;
   scoped_ptr<ToplevelWindowEventHandler> modal_container_handler_;
   scoped_ptr<ToplevelWindowEventHandler> lock_modal_container_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindowController);
 };
 
 }  // namespace internal
 }  // ash
 
 #endif  //  ASH_ROOT_WINDOW_CONTROLLER_H_