cc: Fix use-after-free in test.

cc/trees/layer_tree_host_unittest.cc

 // Copyright 2011 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 <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/location.h"
@@ skipping 2006 matching lines @@
 
 class LayerTreeHostTestAbortedCommitDoesntStallSynchronousCompositor
     : public LayerTreeHostTestAbortedCommitDoesntStall {
  protected:
   void InitializeSettings(LayerTreeSettings* settings) override {
     LayerTreeHostTestAbortedCommitDoesntStall::InitializeSettings(settings);
     settings->using_synchronous_renderer_compositor = true;
   }
 
   void ScheduledActionInvalidateOutputSurface() override {
+    // Do not call ImplThreadTaskRunner after the test ended because of the
+    // possibility of use-after-free due to a race.
+    if (TestEnded())
+      return;
     ImplThreadTaskRunner()->PostTask(
         FROM_HERE,
         base::Bind(
             &LayerTreeHostTestAbortedCommitDoesntStallSynchronousCompositor::
                 CallOnDraw,
             base::Unretained(this)));
   }
 
   void CallOnDraw() {
     // Synchronous compositor does not draw unless told to do so by the output
@@ skipping 4168 matching lines @@
   ScrollAndScaleSet scale_info_;
   ScrollAndScaleSet no_op_info_;
   bool requested_update_layers_;
   int commit_count_;
 };
 
 MULTI_THREAD_TEST_F(LayerTreeHostScrollingAndScalingUpdatesLayers);
 
 }  // namespace
 }  // namespace cc