Use DwmGetCompositionTimingInfo to get vsync info on Windows

ui/surface/accelerated_surface_win.h

 // 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.
 
 #ifndef UI_SURFACE_ACCELERATED_SURFACE_WIN_H_
 #define UI_SURFACE_ACCELERATED_SURFACE_WIN_H_
 
 #include <d3d9.h>
 
 #include "base/callback_forward.h"
@@ skipping 53 matching lines @@
   // presenter has affinity.
   void DoPresentAndAcknowledge(
       const gfx::Size& size,
       int64 surface_handle,
       const base::Callback<void(bool)>& completion_task);
   void DoSuspend();
   void DoPresent(HDC dc, bool* presented);
   bool DoRealPresent(HDC dc);
   void DoReleaseSurface();
 
+  // This gets the timestamp and period of the display's last vsync.
+  // The period is represented as a ratio which, when divided, will give you
+  // the interval in seconds.
+  void GetPresentationStats(base::TimeTicks *timebase,

[jbates, 2012/07/30 18:37:51]

- comments should explicitly say how to calculate the frame interval and give
example values, because it's actually the opposite of what is expected. eg:
interval_in_seconds = interval_denominator/interval_numerator
example values: denominator = 1001, numerator = 60000.
- pointer style is typically TimeTicks* timebase in chromium.

[jbates, 2012/07/30 19:27:00]

Err, except in reverse since you already swap them :)

[brianderson, 2012/07/30 19:38:13]

Yeah, I just swapped them in a recent commit.  Will update comments.

+                            uint32 *interval_numerator,
+                            uint32 *interval_denominator);
+
   // The thread with which this presenter has affinity.
   PresentThread* const present_thread_;
 
   // The window that is presented to.
   gfx::NativeWindow window_;
 
   // The lock is taken while any thread is calling the object, except those that
   // simply post from the main thread to the present thread via the immutable
   // present_thread_ member.
   base::Lock lock_;
@@ skipping 44 matching lines @@
 
   // Indicates that the surface has become invisible.
   void WasHidden();
 
  private:
   const scoped_refptr<AcceleratedPresenter> presenter_;
   DISALLOW_COPY_AND_ASSIGN(AcceleratedSurface);
 };
 
 #endif  // UI_SURFACE_ACCELERATED_SURFACE_WIN_H_