Remove gfx::FrameTime for a single clock source

ui/gfx/frame_time.h

-// Copyright 2013 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.
-
-#ifndef UI_GFX_FRAME_TIME_H
-#define UI_GFX_FRAME_TIME_H
-
-#include "base/time/time.h"
-#include "base/logging.h"
-
-namespace gfx {
-
-// FrameTime::Now() should be used to get timestamps with a timebase that
-// is consistent across the graphics stack.
-class FrameTime {
- public:
-  static base::TimeTicks Now() {
-    return base::TimeTicks::Now();
-  }
-
-#if defined(OS_WIN)
-  static base::TimeTicks FromQPCValue(LONGLONG qpc_value) {
-    DCHECK(TimestampsAreHighRes());
-    return base::TimeTicks::FromQPCValue(qpc_value);
-  }
-#endif
-
-  static bool TimestampsAreHighRes() {
-#if defined(OS_WIN)
-    return base::TimeTicks::IsHighResolution();
-#else
-    // TODO(miu): Mac/Linux always provide high-resolution timestamps.  Consider
-    // returning base::TimeTicks::IsHighResolution() for all platforms.
-    return false;
-#endif
-  }
-};
-
-}
-
-#endif // UI_GFX_FRAME_TIME_H