CC Animations: Fix LayerTreeHostTimelinesTestSetPotentiallyAnimatingOnLacDestruction flakiness.

cc/trees/layer_tree_host_unittest_animation_timelines.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include "cc/animation/animation_curve.h"
 #include "cc/animation/animation_host.h"
 #include "cc/animation/animation_id_provider.h"
 #include "cc/animation/animation_player.h"
@@ skipping 986 matching lines @@
 // An animation finishing during commit can only happen when we have a separate
 // compositor thread.
 MULTI_THREAD_TEST_F(LayerTreeHostTimelinesTestAnimationFinishesDuringCommit);
 
 // Check that SetTransformIsPotentiallyAnimatingChanged is called
 // if we destroy LayerAnimationController and ElementAnimations.
 class LayerTreeHostTimelinesTestSetPotentiallyAnimatingOnLacDestruction
     : public LayerTreeHostTimelinesTest {
  public:
   void SetupTree() override {
+    prev_screen_space_transform_is_animating_ = true;
+    screen_space_transform_animation_stopped_ = false;
+
     LayerTreeHostTimelinesTest::SetupTree();
     AttachPlayersToTimeline();
     player_->AttachLayer(layer_tree_host()->root_layer()->id());
     AddAnimatedTransformToPlayer(player_.get(), 1.0, 5, 5);
   }
 
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
   void CommitCompleteOnThread(LayerTreeHostImpl* host_impl) override {
-    if (host_impl->active_tree()->source_frame_number() == 1) {
-      EXPECT_TRUE(host_impl->active_tree());
-      EXPECT_TRUE(host_impl->active_tree()->root_layer());
-      EXPECT_TRUE(host_impl->pending_tree());
-      EXPECT_TRUE(host_impl->pending_tree()->root_layer());
-
-      EXPECT_EQ(2, host_impl->pending_tree()->source_frame_number());
-
-      EXPECT_TRUE(host_impl->active_tree()
+    if (host_impl->pending_tree()->source_frame_number() <= 1) {
+      EXPECT_TRUE(host_impl->pending_tree()
                       ->root_layer()
                       ->screen_space_transform_is_animating());
+    } else {
       EXPECT_FALSE(host_impl->pending_tree()
                        ->root_layer()
                        ->screen_space_transform_is_animating());
-    } else if (host_impl->active_tree()->source_frame_number() == 2) {
-      EXPECT_FALSE(host_impl->active_tree()
-                       ->root_layer()
-                       ->screen_space_transform_is_animating());
-      EXPECT_FALSE(host_impl->pending_tree()
-                       ->root_layer()
-                       ->screen_space_transform_is_animating());
     }
   }
 
   void DidCommit() override { PostSetNeedsCommitToMainThread(); }
 
   void UpdateLayerTreeHost() override {
     if (layer_tree_host()->source_frame_number() == 2) {
       // Destroy player.
       timeline_->DetachPlayer(player_.get());
       player_ = nullptr;
     }
   }
 
+  DrawResult PrepareToDrawOnThread(LayerTreeHostImpl* host_impl,
+                                   LayerTreeHostImpl::FrameData* frame_data,
+                                   DrawResult draw_result) override {
+    if (!host_impl->active_tree())

[ajuma, 2015/11/23 14:25:28]

Is this needed? (That is, does PrepareToDrawOnThread ever get called when there
isn't an active tree?)

[loyso (OOO), 2015/11/24 00:04:25]

Done.

+      return draw_result;
+
+    const bool screen_space_transform_is_animating =
+        host_impl->active_tree()
+            ->root_layer()
+            ->screen_space_transform_is_animating();
+
+    // Check that screen_space_transform_is_animating changes only once.
+    if (screen_space_transform_is_animating &&
+        prev_screen_space_transform_is_animating_)
+      EXPECT_FALSE(screen_space_transform_animation_stopped_);
+    if (!screen_space_transform_is_animating &&
+        prev_screen_space_transform_is_animating_) {
+      EXPECT_FALSE(screen_space_transform_animation_stopped_);
+      screen_space_transform_animation_stopped_ = true;
+    }
+    if (!screen_space_transform_is_animating &&
+        !prev_screen_space_transform_is_animating_)
+      EXPECT_TRUE(screen_space_transform_animation_stopped_);
+
+    prev_screen_space_transform_is_animating_ =
+        screen_space_transform_is_animating;
+
+    return draw_result;
+  }
+
   void DrawLayersOnThread(LayerTreeHostImpl* host_impl) override {
     if (host_impl->active_tree()->source_frame_number() >= 2)
       EndTest();
   }
 
-  void AfterTest() override {}
+  void AfterTest() override {
+    EXPECT_TRUE(screen_space_transform_animation_stopped_);
+  }
+
+  bool prev_screen_space_transform_is_animating_;
+  bool screen_space_transform_animation_stopped_;
 };
 
 MULTI_THREAD_TEST_F(
     LayerTreeHostTimelinesTestSetPotentiallyAnimatingOnLacDestruction);
 
 // Check that we invalidate property trees on AnimationPlayer::SetNeedsCommit.
 class LayerTreeHostTimelinesTestRebuildPropertyTreesOnAnimationSetNeedsCommit
     : public LayerTreeHostTimelinesTest {
  public:
   void SetupTree() override {
@@ skipping 35 matching lines @@
  private:
   scoped_refptr<Layer> layer_;
   FakeContentLayerClient client_;
 };
 
 MULTI_THREAD_TEST_F(
     LayerTreeHostTimelinesTestRebuildPropertyTreesOnAnimationSetNeedsCommit);
 
 }  // namespace
 }  // namespace cc