cc: Use HighResNow as timebase if it is fast and reliable

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 33 matching lines @@
 #include "cc/trees/layer_tree_host_impl.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/thread_proxy.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "skia/ext/refptr.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "third_party/khronos/GLES2/gl2ext.h"
 #include "third_party/skia/include/core/SkPicture.h"
+#include "ui/gfx/frame_time.h"
 #include "ui/gfx/point_conversions.h"
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/vector2d_conversions.h"
 
 using testing::_;
 using testing::AnyNumber;
 using testing::AtLeast;
 using testing::Mock;
 
 namespace cc {
@@ skipping 933 matching lines @@
 
     PostSetNeedsCommitToMainThread();
   }
 
   virtual void DrawLayersOnThread(LayerTreeHostImpl* impl) OVERRIDE {
     frame_++;
     if (frame_ == 1) {
       first_frame_time_ = impl->CurrentFrameTimeTicks();
       impl->SetNeedsRedraw();
 
-      // Since base::TimeTicks::Now() uses a low-resolution clock on
-      // Windows, we need to make sure that the clock has incremented past
-      // first_frame_time_.
-      while (first_frame_time_ == base::TimeTicks::Now()) {}
+      // Since we might use a low-resolution clock on Windows, we need to
+      // make sure that the clock has incremented past first_frame_time_.
+      while (first_frame_time_ == gfx::FrameTime::Now()) {}
 
       return;
     }
 
     EXPECT_NE(first_frame_time_, impl->CurrentFrameTimeTicks());
     EndTest();
   }
 
   virtual void CommitCompleteOnThread(LayerTreeHostImpl* host_impl) OVERRIDE {
     // Ensure there isn't a commit between the two draws, to ensure that a
@@ skipping 4080 matching lines @@
   size_t second_output_surface_memory_limit_;
   FakeContentLayerClient client_;
   scoped_refptr<FakeContentLayer> root_;
 };
 
 // No output to copy for delegated renderers.
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeHostTestSetMemoryPolicyOnLostOutputSurface);
 
 }  // namespace cc