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

ui/surface/accelerated_surface_win.cc

 // Copyright (c) 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 "ui/surface/accelerated_surface_win.h"
 
 #include <windows.h>
 #include <algorithm>
 
 #include "base/bind.h"
@@ skipping 10 matching lines @@
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/win/wrapped_window_proc.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_util.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/base/win/shell.h"
 #include "ui/events/latency_info.h"
+#include "ui/gfx/frame_time.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/win/dpi.h"
 #include "ui/gfx/win/hwnd_util.h"
 #include "ui/gl/gl_switches.h"
 #include "ui/surface/accelerated_surface_transformer_win.h"
 #include "ui/surface/d3d9_utils_win.h"
 #include "ui/surface/surface_switches.h"
 
 namespace d3d_utils = ui_surface_d3d9_utils;
 
@@ skipping 829 matching lines @@
 
   // I can't figure out how to determine how many scanlines are in the
   // vertical blank so clamp it such that scanline / height <= 1.
   int clamped_scanline = std::min(raster_status.ScanLine, display_mode.Height);
 
   // The Internet says that on some GPUs, the scanline is not available
   // while in the vertical blank.
   if (raster_status.InVBlank)
     clamped_scanline = display_mode.Height;
 
-  base::TimeTicks current_time = base::TimeTicks::HighResNow();
-
   // Figure out approximately how far back in time the last vsync was based on
   // the ratio of the raster scanline to the display height.
   base::TimeTicks last_vsync_time;
   base::TimeDelta refresh_period;
+
   if (display_mode.Height) {
+    refresh_period = base::TimeDelta::FromMicroseconds(
+        1000000 / display_mode.RefreshRate);
+    // If FrameTime is not high resolution, we use a timebase of zero to avoid
+    // introducing jitter into our frame start times.
+    if (gfx::FrameTime::TimestampsAreHighRes()) {
+      base::TimeTicks current_time = gfx::FrameTime::Now();
       last_vsync_time = current_time -
         base::TimeDelta::FromMilliseconds((clamped_scanline * 1000) /
             (display_mode.RefreshRate * display_mode.Height));
-      refresh_period = base::TimeDelta::FromMicroseconds(
-          1000000 / display_mode.RefreshRate);
+    }
   }
 
   // Wait for the StretchRect to complete before notifying the GPU process
   // that it is safe to write to its backing store again.
   {
     TRACE_EVENT0("gpu", "spin");
 
     do {
       hr = present_thread_->query()->GetData(NULL, 0, D3DGETDATA_FLUSH);
       if (hr == S_FALSE) {
@@ skipping 192 matching lines @@
   presenter_->Suspend();
 }
 
 void AcceleratedSurface::WasHidden() {
   presenter_->WasHidden();
 }
 
 void AcceleratedSurface::SetIsSessionLocked(bool locked) {
   presenter_->SetIsSessionLocked(locked);
 }