cc: Fix use-after-frees for LayerTreeHostAnimationTest.

cc/trees/layer_tree_host_unittest_animation.cc

 // Copyright 2012 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 <stdint.h>
 
 #include "cc/animation/animation_curve.h"
 #include "cc/animation/animation_host.h"
@@ skipping 1326 matching lines @@
         break;
     }
   }
 
   void DrawLayersOnThread(LayerTreeHostImpl* host_impl) override {
     // After both animations have started, verify that they have valid
     // start times.
     if (host_impl->active_tree()->source_frame_number() < 2)
       return;
 
-    // Animation state is updated after drawing.
-    ImplThreadTaskRunner()->PostTask(
-        FROM_HERE,
-        base::Bind(&LayerTreeHostAnimationTestAddAnimationAfterAnimating::
-                       CheckAnimations,
-                   base::Unretained(this), host_impl));
+    // Animation state is updated after drawing. Only do this once.
+    if (!TestEnded()) {
+      ImplThreadTaskRunner()->PostTask(
+          FROM_HERE,
+          base::Bind(&LayerTreeHostAnimationTestAddAnimationAfterAnimating::
+                         CheckAnimations,
+                     base::Unretained(this), host_impl));
+    }
   }
 
   void CheckAnimations(LayerTreeHostImpl* host_impl) {
     AnimationHost::ElementToAnimationsMap element_animations_copy =
         host_impl->animation_host()->active_element_animations_for_testing();
     EXPECT_EQ(2u, element_animations_copy.size());
     for (auto& it : element_animations_copy) {
       ElementId id = it.first;
       if (id ==
           host_impl->active_tree()->root_layer_for_testing()->element_id()) {
@@ skipping 492 matching lines @@
  private:
   scoped_refptr<Layer> layer_;
   FakeContentLayerClient client_;
 };
 
 MULTI_THREAD_TEST_F(
     LayerTreeHostAnimationTestRebuildPropertyTreesOnAnimationSetNeedsCommit);
 
 }  // namespace
 }  // namespace cc