Improve existing lock transition - remove black splash.

ash/wm/power_button_controller.cc

Index: ash/wm/power_button_controller.cc
diff --git a/ash/wm/power_button_controller.cc b/ash/wm/power_button_controller.cc
index 55d59931ee8f75ef047a408b53b320f0f9914044..05ce1363ce6b37d32b1e366ea12e092816c7c8cc 100644
--- a/ash/wm/power_button_controller.cc
+++ b/ash/wm/power_button_controller.cc
@@ -164,6 +164,13 @@ void GetContainers(PowerButtonController::ContainerGroup group,
                    aura::Window::Windows* containers) {
   aura::RootWindow* root_window = Shell::GetPrimaryRootWindow();
 
+  aura::Window* wallpaper_container = Shell::GetContainer(
+      root_window,
+      internal::kShellWindowId_DesktopBackgroundContainer);
+  aura::Window* lock_wallpaper_container = Shell::GetContainer(
+      root_window,
+      internal::kShellWindowId_LockScreenBackgroundContainer);
+
   aura::Window* non_lock_screen_containers = Shell::GetContainer(
       root_window,
       internal::kShellWindowId_NonLockScreenContainersContainer);
@@ -177,18 +184,24 @@ void GetContainers(PowerButtonController::ContainerGroup group,
   containers->clear();
   switch (group) {
     case PowerButtonController::ALL_CONTAINERS:
+      containers->push_back(wallpaper_container);
       containers->push_back(non_lock_screen_containers);
+      containers->push_back(lock_wallpaper_container);
       containers->push_back(lock_screen_containers);
       containers->push_back(lock_screen_related_containers);
       break;
-    case PowerButtonController::SCREEN_LOCKER_CONTAINERS:
+    case PowerButtonController::SCREEN_LOCKER_CONTAINERS_EXCEPT_WALLPAPER:
       containers->push_back(lock_screen_containers);
       break;
     case PowerButtonController::SCREEN_LOCKER_AND_RELATED_CONTAINERS:
+      containers->push_back(lock_wallpaper_container);
       containers->push_back(lock_screen_containers);
       containers->push_back(lock_screen_related_containers);
       break;
     case PowerButtonController::ALL_BUT_SCREEN_LOCKER_AND_RELATED_CONTAINERS:
+      // Doesn't include wallpaper_container as it is now excluded from
+      // these animations (i.e. restore).
+      // New lock/shutdown transition may change that.
       containers->push_back(non_lock_screen_containers);
       break;
     default:
@@ -333,7 +346,8 @@ void PowerButtonController::OnLockStateChanged(bool locked) {
   }
 
   if (locked) {
-    StartAnimation(SCREEN_LOCKER_CONTAINERS, ANIMATION_FADE_IN);
+    StartAnimation(SCREEN_LOCKER_CONTAINERS_EXCEPT_WALLPAPER,
+                   ANIMATION_FADE_IN);
     lock_timer_.Stop();
     lock_fail_timer_.Stop();
 
@@ -368,7 +382,8 @@ void PowerButtonController::OnStartingLock() {
                  ANIMATION_FAST_CLOSE);
 
   // Hide the screen locker containers so we can make them fade in later.
-  StartAnimation(SCREEN_LOCKER_CONTAINERS, ANIMATION_HIDE);
+  StartAnimation(SCREEN_LOCKER_CONTAINERS_EXCEPT_WALLPAPER,
+                 ANIMATION_HIDE);
 }
 
 void PowerButtonController::OnPowerButtonEvent(