Improve existing lock transition - remove black splash.

ash/root_window_controller.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/root_window_controller.h"
 
 #include <vector>
 
 #include "ash/desktop_background/desktop_background_widget_controller.h"
 #include "ash/display/display_controller.h"
@@ skipping 116 matching lines @@
   container->SetProperty(internal::kUsesScreenCoordinatesKey, true);
 }
 
 // Creates each of the special window containers that holds windows of various
 // types in the shell UI.
 void CreateContainersInRootWindow(aura::RootWindow* root_window) {
   // These containers are just used by PowerButtonController to animate groups
   // of containers simultaneously without messing up the current transformations
   // on those containers.  These are direct children of the root window; all of
   // the other containers are their children.
+  // Desktop and lock screen background containers are not part of the
+  // lock animation so they are not included in those animate groups.
+
+  aura::Window* desktop_background_containers = CreateContainer(
+      internal::kShellWindowId_DesktopBackgroundContainer,
+      "DesktopBackgroundContainer",
+      root_window);
+  SetChildWindowVisibilityChangesAnimated(desktop_background_containers);
+
   aura::Window* non_lock_screen_containers = CreateContainer(
       internal::kShellWindowId_NonLockScreenContainersContainer,
       "NonLockScreenContainersContainer",
       root_window);
+
+  aura::Window* lock_background_containers = CreateContainer(

[Daniel Erat, 2012/09/04 16:58:59]

Nikita and I discussed this over IM.  I didn't think that this container is
necessary anymore; it seems like the wallpaper should just be able to always
stay in DesktopBackgroundContainer.  Apparently we want to move the wallpaper
here when the screen is locked to make sure that there's an opaque layer
occluding the non-lock-screen layers, though.  It'd be good to document this in
a comment somewhere.

[Nikita (slow), 2012/09/04 17:36:42]

Done.

+      internal::kShellWindowId_LockScreenBackgroundContainer,
+      "LockScreenBackgroundContainer",
+      root_window);
+  SetChildWindowVisibilityChangesAnimated(lock_background_containers);
+
   aura::Window* lock_screen_containers = CreateContainer(
       internal::kShellWindowId_LockScreenContainersContainer,
       "LockScreenContainersContainer",
       root_window);
   aura::Window* lock_screen_related_containers = CreateContainer(
       internal::kShellWindowId_LockScreenRelatedContainersContainer,
       "LockScreenRelatedContainersContainer",
       root_window);
 
   CreateContainer(internal::kShellWindowId_UnparentedControlContainer,
                   "UnparentedControlContainer",
                   non_lock_screen_containers);
 
   CreateContainer(internal::kShellWindowId_SystemBackgroundContainer,
                   "SystemBackgroundContainer", non_lock_screen_containers);
 
-  aura::Window* desktop_background_containers = CreateContainer(
-      internal::kShellWindowId_DesktopBackgroundContainer,
-      "DesktopBackgroundContainer",
-      non_lock_screen_containers);
-  SetChildWindowVisibilityChangesAnimated(desktop_background_containers);
-
   aura::Window* default_container = CreateContainer(
       internal::kShellWindowId_DefaultContainer,
       "DefaultContainer",
       non_lock_screen_containers);
   default_container->SetEventFilter(
       new ToplevelWindowEventFilter(default_container));
   SetChildWindowVisibilityChangesAnimated(default_container);
   SetUsesScreenCoordinates(default_container);
 
   aura::Window* always_on_top_container = CreateContainer(
@@ skipping 31 matching lines @@
       new internal::SystemModalContainerLayoutManager(modal_container));
   SetChildWindowVisibilityChangesAnimated(modal_container);
   SetUsesScreenCoordinates(modal_container);
 
   aura::Window* input_method_container = CreateContainer(
       internal::kShellWindowId_InputMethodContainer,
       "InputMethodContainer",
       non_lock_screen_containers);
   SetUsesScreenCoordinates(input_method_container);
 
-  aura::Window* lock_background_containers = CreateContainer(
-      internal::kShellWindowId_LockScreenBackgroundContainer,
-      "LockScreenBackgroundContainer",
-      lock_screen_containers);
-
-  SetChildWindowVisibilityChangesAnimated(lock_background_containers);
-
   // TODO(beng): Figure out if we can make this use
   // SystemModalContainerEventFilter instead of stops_event_propagation.
   aura::Window* lock_container = CreateContainer(
       internal::kShellWindowId_LockScreenContainer,
       "LockScreenContainer",
       lock_screen_containers);
   lock_container->SetLayoutManager(
       new internal::BaseLayoutManager(root_window));
   SetUsesScreenCoordinates(lock_container);
   // TODO(beng): stopsevents
@@ skipping 135 matching lines @@
   // Restore focused or active window if it's still alive.
   if (focused && tracker.Contains(focused) && dst->Contains(focused)) {
     dst->GetFocusManager()->SetFocusedWindow(focused, NULL);
   } else if (active && tracker.Contains(active) && dst->Contains(active)) {
     activation_client->ActivateWindow(active);
   }
 }
 
 }  // namespace internal
 }  // namespace ash