ARC Toast: Prevent onClosed event from being called multiple times

ash/system/toast/toast_overlay.cc

Index: ash/system/toast/toast_overlay.cc
diff --git a/ash/system/toast/toast_overlay.cc b/ash/system/toast/toast_overlay.cc
index 45612b57b513d21e00bacf4f01d8f39f17b6d039..9ce8635397e4715ee24ef762cfbd9f1ab6047eaf 100644
--- a/ash/system/toast/toast_overlay.cc
+++ b/ash/system/toast/toast_overlay.cc
@@ -213,14 +213,16 @@ ToastOverlay::~ToastOverlay() {
 }
 
 void ToastOverlay::Show(bool visible) {
-  if (is_visible_ == visible)
+  if (overlay_widget_->GetLayer()->GetTargetVisibility() == visible)
     return;
 
-  is_visible_ = visible;
+  ui::LayerAnimator* animator = overlay_widget_->GetLayer()->GetAnimator();
+  if (animator && animator->is_animating())
+    animator->StopAnimating();
 
   overlay_widget_->GetLayer()->GetAnimator()->AddObserver(this);
 

[oshima, 2016/04/13 10:03:18]

You can use ImplicitAnimationObserver to implement an action to take upon
completion. 

ui::ScopedAnimationSettings settings(animator);
settings.AddObserver(your_observer);


here. Then you should be able to check if it's still animating in Completed to
make sure that there is another animation going. 

[yoshiki, 2016/04/14 14:08:58]

Done.

-  if (is_visible_)
+  if (visible)
     overlay_widget_->Show();
   else
     overlay_widget_->Hide();
@@ -238,25 +240,40 @@ gfx::Rect ToastOverlay::CalculateOverlayBounds() {
   return bounds;
 }
 
+void ToastOverlay::OnLayerAnimationStarted(
+    ui::LayerAnimationSequence* sequence) {
+  inflight_animations_.insert(sequence);
+}
+
+bool ToastOverlay::RequiresNotificationWhenAnimatorDestroyed() const {
+  return true;
+}
+
 void ToastOverlay::OnLayerAnimationEnded(ui::LayerAnimationSequence* sequence) {
-  ui::LayerAnimator* animator = overlay_widget_->GetLayer()->GetAnimator();
-  if (animator)
-    animator->RemoveObserver(this);
-  if (!is_visible_) {
-    // Acync operation, since delegate may remove this instance and removing
-    // this here causes crash.
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE,
-        base::Bind(&Delegate::OnClosed,
-                   base::Unretained(delegate_) /* |delegate| lives longer */));
+  inflight_animations_.erase(sequence);
+  OnAnimationStopped();
+}
+
+void ToastOverlay::OnAnimationStopped() {
+  if (inflight_animations_.empty()) {
+    ui::LayerAnimator* animator = overlay_widget_->GetLayer()->GetAnimator();
+    if (animator)
+      animator->RemoveObserver(this);
+    if (!overlay_widget_->GetLayer()->GetTargetVisibility()) {
+      // Acync operation, since delegate may remove this instance and removing
+      // this here causes crash.
+      base::ThreadTaskRunnerHandle::Get()->PostTask(
+          FROM_HERE, base::Bind(&Delegate::OnClosed,
+                                base::Unretained(
+                                    delegate_) /* |delegate| lives longer */));
+    }
   }
 }
 
 void ToastOverlay::OnLayerAnimationAborted(
     ui::LayerAnimationSequence* sequence) {
-  ui::LayerAnimator* animator = overlay_widget_->GetLayer()->GetAnimator();
-  if (animator)
-    animator->RemoveObserver(this);
+  inflight_animations_.erase(sequence);
+  OnAnimationStopped();
 }
 
 void ToastOverlay::OnLayerAnimationScheduled(