Use DwmGetCompositionTimingInfo to get vsync info on Windows

ui/surface/accelerated_surface_win.cc

Index: ui/surface/accelerated_surface_win.cc
diff --git a/ui/surface/accelerated_surface_win.cc b/ui/surface/accelerated_surface_win.cc
index da77ac502f42fc2ca34eff16c073d8cd750e12de..a82018304d1837ea6b912f441aa147cd4c898a39 100644
--- a/ui/surface/accelerated_surface_win.cc
+++ b/ui/surface/accelerated_surface_win.cc
@@ -4,6 +4,7 @@
 
 #include "ui/surface/accelerated_surface_win.h"
 
+#include <dwmapi.h>
 #include <windows.h>
 #include <algorithm>
 
@@ -833,6 +834,28 @@ void AcceleratedPresenter::DoReleaseSurface() {
   source_texture_.Release();
 }
 
+void AcceleratedPresenter::GetPresentationStats(base::TimeTicks *timebase,
+                                                uint32 *interval_n,
+                                                uint32 *interval_d) {
+  lock_.AssertAcquired();
+
+  DWM_TIMING_INFO timingInfo;
+  timingInfo.cbSize = sizeof(timingInfo);
+  HRESULT gctiResult = DwmGetCompositionTimingInfo(window_, &timingInfo);
+  if (gctiResult != S_OK)
+      return;

[jbates, 2012/07/28 01:35:30]

2 space indent

+
+  // TODO: For scheduling purposes we can choose to synchronize to the
+  // vblank or composition time.  If the composition time jitters, it may
+  // be better to rely on the vblank only.  It may be even better to have
+  // animations depend on the vblank, but touch events and rendering to
+  // depend on composition time eventually.
+  *timebase = base::TimeTicks::FromQPCValue(
+                static_cast<LONGLONG>(timingInfo.qpcCompose));
+  *interval_n = timingInfo.rateCompose.uiNumerator;
+  *interval_d = timingInfo.rateCompose.uiDenominator;
+}
+
 AcceleratedSurface::AcceleratedSurface(gfx::NativeWindow window)
     : presenter_(g_accelerated_presenter_map.Pointer()->CreatePresenter(
           window)) {