Fix black background when locking with fullscreen window:

ui/compositor/layer_animation_observer.cc

Index: ui/compositor/layer_animation_observer.cc
diff --git a/ui/compositor/layer_animation_observer.cc b/ui/compositor/layer_animation_observer.cc
index 2d7402b5f1aee921dab7e68d8a1623b252299470..bb0771a476298f678d1cdb11d0d2e4a362fe4b3d 100644
--- a/ui/compositor/layer_animation_observer.cc
+++ b/ui/compositor/layer_animation_observer.cc
@@ -120,4 +120,113 @@ void ImplicitAnimationObserver::CheckCompleted() {
   }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// AnimationFinishedObserver
+
+AnimationFinishedObserver::AnimationFinishedObserver(
+    base::Callback<void(void)> &callback)
+    : callback_(callback),
+      sequences_attached_(0),
+      sequences_completed_(0),
+      paused_(false) {
+}
+
+AnimationFinishedObserver::~AnimationFinishedObserver() {
+}
+
+void AnimationFinishedObserver::Pause() {
+  paused_ = true;
+}
+
+void AnimationFinishedObserver::Unpause() {
+  if (!paused_)
+    return;
+  paused_ = false;
+  if (sequences_completed_ == sequences_attached_) {
+    callback_.Run();
+    delete this;
+  }
+}
+
+void AnimationFinishedObserver::OnLayerAnimationEnded(
+    ui::LayerAnimationSequence* seq) {
+  sequences_completed_++;
+  if ((sequences_completed_ == sequences_attached_) && !paused_) {
+    callback_.Run();
+    delete this;
+  }
+}
+
+void AnimationFinishedObserver::OnLayerAnimationAborted(
+    ui::LayerAnimationSequence* seq) {
+  sequences_completed_++;
+  if ((sequences_completed_ == sequences_attached_) && !paused_)
+    delete this;
+}
+
+void AnimationFinishedObserver::OnAttachedToSequence(
+    LayerAnimationSequence* sequence) {
+  LayerAnimationObserver::OnAttachedToSequence(sequence);
+  sequences_attached_++;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// AnimationAbortedObserver
+
+AnimationAbortedObserver::AnimationAbortedObserver(
+    base::Callback<void(void)> &callback)
+    : callback_(callback),
+      sequences_attached_(0),
+      sequences_completed_(0),
+      aborted_(false) {
+}
+
+AnimationAbortedObserver::~AnimationAbortedObserver() {
+  if (sequences_completed_ != sequences_attached_) {
+    if (aborted_)
+      callback_.Run();
+  }
+}
+
+void AnimationAbortedObserver::Pause() {
+  paused_ = true;
+}
+
+void AnimationAbortedObserver::Unpause() {
+  if (!paused_)
+    return;
+  paused_ = false;
+  if (sequences_completed_ == sequences_attached_) {
+    if (aborted_)
+      callback_.Run();
+    delete this;
+  }
+}
+
+void AnimationAbortedObserver::OnLayerAnimationEnded(
+    ui::LayerAnimationSequence* seq) {
+  sequences_completed_++;
+  if ((sequences_completed_ == sequences_attached_) && !paused_) {
+    if (aborted_)
+      callback_.Run();
+    delete this;
+  }
+}
+
+void AnimationAbortedObserver::OnLayerAnimationAborted(
+    ui::LayerAnimationSequence* seq) {
+  aborted_ = true;
+  sequences_completed_++;
+  if ((sequences_completed_ == sequences_attached_) && !paused_) {
+    callback_.Run();
+    delete this;
+  }
+}
+
+void AnimationAbortedObserver::OnAttachedToSequence(
+    LayerAnimationSequence* sequence) {
+  LayerAnimationObserver::OnAttachedToSequence(sequence);
+  sequences_attached_++;
+}
+
 }  // namespace ui