Revert of Disable LayerTreeHostTestDeferCommits since it is flaky on Win.

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/synchronization/lock.h"
@@ skipping 2058 matching lines @@
   void AfterTest() override {
     EXPECT_GE(3, num_will_begin_impl_frame_);
     EXPECT_EQ(2, num_send_begin_main_frame_);
   }
 
  private:
   int num_will_begin_impl_frame_;
   int num_send_begin_main_frame_;
 };
 
-#if !defined(OS_WIN)
-// Flaky on Win: crbug/453787.
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestDeferCommits);
-#endif
 
 class LayerTreeHostWithProxy : public LayerTreeHost {
  public:
   LayerTreeHostWithProxy(FakeLayerTreeHostClient* client,
                          const LayerTreeSettings& settings,
                          scoped_ptr<FakeProxy> proxy)
       : LayerTreeHost(client, NULL, NULL, settings) {
     proxy->SetLayerTreeHost(this);
     client->SetLayerTreeHost(this);
     InitializeForTesting(proxy.Pass());
@@ skipping 4104 matching lines @@
 
   void AfterTest() override { EXPECT_TRUE(did_commit_); }
 
  private:
   bool did_commit_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestNoTasksBetweenWillAndDidCommit);
 
 }  // namespace cc