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..748b2e71d36f3ff03b0802e18112e33e6bd25c8d 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 +834,24 @@ void AcceleratedPresenter::DoReleaseSurface() {
   source_texture_.Release();
 }
 
+void AcceleratedPresenter::GetPresentationStats(base::TimeTicks *timebase,
+                                                uint32 *interval_numerator,
+                                                uint32 *interval_denominator) {
+  lock_.AssertAcquired();
+
+  DWM_TIMING_INFO timingInfo;

[apatrick_chromium, 2012/07/30 19:43:31]

timing_info

+  timingInfo.cbSize = sizeof(timingInfo);
+  HRESULT gctiResult = DwmGetCompositionTimingInfo(window_, &timingInfo);

[apatrick_chromium, 2012/07/30 19:43:31]

I'd just call this result. otherwise gcti_result.

[brianderson, 2012/07/30 20:16:39]

Artifact of previous code that had multiple result types.  Fixed.

+  if (gctiResult != S_OK)
+    return;
+
+  *timebase = base::TimeTicks::FromQPCValue(
+      static_cast<LONGLONG>(timingInfo.qpcVBlank));
+  // Swap the numerator/denominator to convert frequency to period.
+  *interval_numerator = timingInfo.rateRefresh.uiDenominator;
+  *interval_denominator = timingInfo.rateRefresh.uiNumerator;
+}
+
 AcceleratedSurface::AcceleratedSurface(gfx::NativeWindow window)
     : presenter_(g_accelerated_presenter_map.Pointer()->CreatePresenter(
           window)) {