Fix crash in Assistant's AnimatedContainerView.

Crash was caused by overlapping animate-out animations.

Bug: b:157521638, b:151979172, b:145136105
Change-Id: I71787905346a29a3d238d172a5660e252d3c4f01
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2216617
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Jeroen Dhollander <jeroendh@google.com>
Cr-Commit-Position: refs/heads/master@{#772418}

ash/assistant/ui/main_stage/animated_container_view.cc

@@ -177,10 +177,10 @@ void AnimatedContainerView::ChangeResponse(
   // view hierarchy can be removed before the underlying views are destroyed.
   queued_response_ = response;
 
-  // If we are currently fading out the old content, don't interrupt it.
-  // When the fading out is completed, it will detect we've got a queued
-  // response and animate it in.
-  if (fade_out_in_progress_)
+  // If we are currently animating-/fading-out the old content, don't interrupt
+  // it. When the animating-/fading-out is completed, it will detect we've got a
+  // queued response and animate it in.
+  if (animate_out_in_progress_ || fade_out_in_progress_)
     return;
 
   // If we don't have any pre-existing content, there is nothing to animate off
@@ -190,6 +190,8 @@ void AnimatedContainerView::ChangeResponse(
     return;
   }
 
+  animate_out_in_progress_ = true;
+
   // There is a previous response on stage, so we'll animate it off before
   // adding the new response. The new response will be added upon invocation
   // of the exit animation ended callback.
@@ -332,6 +334,8 @@ bool AnimatedContainerView::AnimateOutObserverCallback(
   if (!weak_ptr)
     return true;
 
+  weak_ptr->animate_out_in_progress_ = false;
+
   // If the exit animation was aborted, we just return true to delete our
   // observer. No further action is needed.
   if (observer.aborted_count())

ash/assistant/ui/main_stage/animated_container_view.h

@@ -151,6 +151,9 @@ class COMPONENT_EXPORT(ASSISTANT_UI) AnimatedContainerView
   // reduces layout passes.
   bool propagate_preferred_size_changed_ = true;
 
+  // Whether the animate-out animation is in progress.
+  bool animate_out_in_progress_ = false;
+
   // Whether the fade-out animation is in progress.
   bool fade_out_in_progress_ = false;