Fix white flash when user sings out and wallpaper animation regression

ash/desktop_background/desktop_background_view.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 "ash/desktop_background/desktop_background_view.h"
 
 #include <limits>
 
 #include "ash/ash_export.h"
 #include "ash/desktop_background/desktop_background_controller.h"
+#include "ash/desktop_background/desktop_background_widget_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/window_animations.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
 #include "grit/ui_resources.h"
 #include "ui/aura/root_window.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_observer.h"
@@ skipping 15 matching lines @@
         container_id_(container_id),
         desktop_widget_(desktop_widget) {
   }
 
   virtual ~ShowWallpaperAnimationObserver() {
   }
 
  private:
   // Overridden from ui::ImplicitAnimationObserver:
   virtual void OnImplicitAnimationsCompleted() OVERRIDE {
-    ash::Shell::GetInstance()->
-        user_wallpaper_delegate()->OnWallpaperAnimationFinished();
+    ash::Shell* shell = ash::Shell::GetInstance();
+    shell->user_wallpaper_delegate()->OnWallpaperAnimationFinished();
+    // Only removes old component when wallpaper animation finished. If we
+    // remove the old one too early, there will be a white flash during
+    // animation.
+    shell->desktop_background_controller()->
+        SetComponentForRootWindow(root_window_);
 
     MessageLoop::current()->DeleteSoon(FROM_HERE, this);
   }
 
   aura::RootWindow* root_window_;
   int container_id_;
   views::Widget* desktop_widget_;
 
   DISALLOW_COPY_AND_ASSIGN(ShowWallpaperAnimationObserver);
 };
@@ skipping 88 matching lines @@
   params.delegate = view;
   if (controller->GetWallpaper().empty())
     params.transparent = true;
   params.parent = root_window->GetChildById(container_id);
   desktop_widget->Init(params);
   desktop_widget->SetContentsView(view);
   ash::WindowVisibilityAnimationType animation_type =
       ash::Shell::GetInstance()->user_wallpaper_delegate()->GetAnimationType();
   ash::SetWindowVisibilityAnimationType(desktop_widget->GetNativeView(),
                                         animation_type);
-  ash::SetWindowVisibilityAnimationTransition(desktop_widget->GetNativeView(),
-                                              ash::ANIMATE_SHOW);
+  // Disable animation when creating the first widget. Otherwise, wallpaper
+  // will animate from a white screen. Note that boot animation is different.
+  // It animates from a white background.
+  if (animation_type == ash::WINDOW_VISIBILITY_ANIMATION_TYPE_FADE &&
+      NULL == root_window->GetProperty(internal::kWindowDesktopComponent)) {
+    ash::SetWindowVisibilityAnimationTransition(desktop_widget->GetNativeView(),
+                                                ash::ANIMATE_NONE);
+  } else {
+    ash::SetWindowVisibilityAnimationTransition(desktop_widget->GetNativeView(),
+                                                ash::ANIMATE_SHOW);
+  }
   desktop_widget->SetBounds(params.parent->bounds());
   ui::ScopedLayerAnimationSettings settings(
       desktop_widget->GetNativeView()->layer()->GetAnimator());
   settings.SetPreemptionStrategy(ui::LayerAnimator::ENQUEUE_NEW_ANIMATION);
   settings.AddObserver(new ShowWallpaperAnimationObserver(root_window,
                                                           container_id,
                                                           desktop_widget));
   desktop_widget->Show();
   desktop_widget->GetNativeView()->SetName("DesktopBackgroundView");
   return desktop_widget;
 }
 
 }  // namespace internal
 }  // namespace ash