Fix black background when locking with fullscreen window:

ash/wm/session_state_animator.cc

Index: ash/wm/session_state_animator.cc
diff --git a/ash/wm/session_state_animator.cc b/ash/wm/session_state_animator.cc
index 6f55b90a6b5f965c84df2702587cad6fe5f375b1..694996ce9731f616a65f3fa53c15a57590745821 100644
--- a/ash/wm/session_state_animator.cc
+++ b/ash/wm/session_state_animator.cc
@@ -120,15 +120,16 @@ void StartPartialFadeAnimation(aura::Window* window,
     sequence->AddObserver(observer);
 }
 
-// Fades |window| in to full opacity over |duration|.
-void FadeInWindow(aura::Window* window,
-                  base::TimeDelta duration,
-                  ui::LayerAnimationObserver* observer) {
+// Fades |window| in to |opacity| over |duration|.
+void StartOpacityAnimationForWindow(aura::Window* window,
+                                    float opacity,
+                                    base::TimeDelta duration,
+                                    ui::LayerAnimationObserver* observer) {
   ui::LayerAnimator* animator = window->layer()->GetAnimator();
   animator->set_preemption_strategy(
       ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
   ui::LayerAnimationSequence* sequence = new ui::LayerAnimationSequence(
-      ui::LayerAnimationElement::CreateOpacityElement(1.0, duration));
+      ui::LayerAnimationElement::CreateOpacityElement(opacity, duration));
   animator->StartAnimation(sequence);
   if (observer)
     sequence->AddObserver(observer);
@@ -299,6 +300,10 @@ bool IsLayerAnimated(ui::Layer* layer,
       if (layer->GetTargetOpacity() < 0.9999)
         return false;
       break;
+    case SessionStateAnimator::ANIMATION_FADE_OUT:
+      if (layer->GetTargetOpacity() > 0.0001)
+        return false;
+      break;
     case SessionStateAnimator::ANIMATION_HIDE_IMMEDIATELY:
       if (layer->GetTargetOpacity() > 0.0001)
         return false;
@@ -458,11 +463,6 @@ void SessionStateAnimator::GetContainers(int container_mask,
         root_window,
         internal::kShellWindowId_LockScreenRelatedContainersContainer));
   }
-  if (container_mask & LOCK_SCREEN_SYSTEM_FOREGROUND) {
-    containers->push_back(Shell::GetContainer(
-        root_window,
-        internal::kShellWindowId_PowerButtonAnimationContainer));
-  }
 }
 
 void SessionStateAnimator::StartAnimation(int container_mask,
@@ -492,6 +492,19 @@ void SessionStateAnimator::StartAnimationWithCallback(
   }
 }
 
+void SessionStateAnimator::StartAnimationWithObserver(
+    int container_mask,
+    AnimationType type,
+    AnimationSpeed speed,
+    ui::LayerAnimationObserver* observer) {
+  aura::Window::Windows containers;
+  GetContainers(container_mask, &containers);
+  for (aura::Window::Windows::const_iterator it = containers.begin();
+       it != containers.end(); ++it) {
+    RunAnimationForWindow(*it, type, speed, observer);
+  }
+}
+
 void SessionStateAnimator::StartGlobalAnimation(AnimationType type,
                                                 AnimationSpeed speed) {
   aura::RootWindow* root_window = Shell::GetPrimaryRootWindow();
@@ -516,7 +529,10 @@ void SessionStateAnimator::RunAnimationForWindow(
       StartFastCloseAnimationForWindow(window, duration, observer);
       break;
     case ANIMATION_FADE_IN:
-      FadeInWindow(window, duration, observer);
+      StartOpacityAnimationForWindow(window, 1.0, duration, observer);
+      break;
+    case ANIMATION_FADE_OUT:
+      StartOpacityAnimationForWindow(window, 0.0, duration, observer);
       break;
     case ANIMATION_HIDE_IMMEDIATELY:
       DCHECK_EQ(speed, ANIMATION_SPEED_IMMEDIATE);