Hook up Mac OSX VSync parameters to compositor thread

content/browser/renderer_host/render_widget_host_view_mac.mm

 // 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 "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 1011 matching lines @@
 }
 
 void RenderWidgetHostViewMac::AckPendingSwapBuffers() {
   TRACE_EVENT0("browser", "RenderWidgetHostViewMac::AckPendingSwapBuffers");
   while (!pending_swap_buffers_acks_.empty()) {
     if (pending_swap_buffers_acks_.front().first != 0) {
       RenderWidgetHostImpl::AcknowledgeBufferPresent(
           pending_swap_buffers_acks_.front().first,
           pending_swap_buffers_acks_.front().second,
           0);
-      if (render_widget_host_)
+      if (render_widget_host_) {
         render_widget_host_->AcknowledgeSwapBuffersToRenderer();
+
+        // Send VSync parameters to compositor thread.
+        if (compositing_iosurface_.get()) {
+          base::TimeTicks timebase;
+          uint32 numerator = 0, denominator = 0;
+          compositing_iosurface_->GetVSyncParameters(&timebase,
+                                                     &numerator,
+                                                     &denominator);
+          if (numerator > 0 && denominator > 0) {
+            int64 interval_micros =
+                1000000 * static_cast<int64>(numerator) / denominator;
+            render_widget_host_->UpdateVSyncParameters(
+                timebase, base::TimeDelta::FromMicroseconds(interval_micros));
+          }
+        }
+      }
     }
     pending_swap_buffers_acks_.erase(pending_swap_buffers_acks_.begin());
   }
 }
 
 bool RenderWidgetHostViewMac::GetLineBreakIndex(
     const std::vector<gfx::Rect>& bounds,
     const ui::Range& range,
     size_t* line_break_point) {
   DCHECK(line_break_point);
@@ skipping 2212 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end