Send vsync timebase updates to the browser compositor

content/common/gpu/image_transport_surface.cc

Index: content/common/gpu/image_transport_surface.cc
diff --git a/content/common/gpu/image_transport_surface.cc b/content/common/gpu/image_transport_surface.cc
index dce01a234876b204cbd5f8ed3ccb2e139855893a..a11ad86720d6eaf3593d70312880d25f402868e7 100644
--- a/content/common/gpu/image_transport_surface.cc
+++ b/content/common/gpu/image_transport_surface.cc
@@ -157,6 +157,12 @@ void ImageTransportHelper::SendResizeView(const gfx::Size& size) {
                                            size));
 }
 
+void ImageTransportHelper::SendUpdateVSyncParameters(
+      base::TimeTicks timebase, base::TimeDelta interval) {
+  manager_->Send(new GpuHostMsg_UpdateVSyncParameters(timebase,
+                                                      interval));
+}
+
 void ImageTransportHelper::SetScheduled(bool is_scheduled) {
   gpu::GpuScheduler* scheduler = Scheduler();
   if (!scheduler)
@@ -270,6 +276,7 @@ void PassThroughImageTransportSurface::Destroy() {
 
 bool PassThroughImageTransportSurface::SwapBuffers() {
   bool result = gfx::GLSurfaceAdapter::SwapBuffers();
+  SendVSyncUpdateIfAvailable();
 
   if (transport_) {
     // Round trip to the browser UI thread, for throttling, by sending a dummy
@@ -286,6 +293,7 @@ bool PassThroughImageTransportSurface::SwapBuffers() {
 bool PassThroughImageTransportSurface::PostSubBuffer(
     int x, int y, int width, int height) {
   bool result = gfx::GLSurfaceAdapter::PostSubBuffer(x, y, width, height);
+  SendVSyncUpdateIfAvailable();
 
   if (transport_) {
     // Round trip to the browser UI thread, for throttling, by sending a dummy
@@ -340,6 +348,24 @@ gfx::Size PassThroughImageTransportSurface::GetSize() {
 
 PassThroughImageTransportSurface::~PassThroughImageTransportSurface() {}
 
+void PassThroughImageTransportSurface::SendVSyncUpdateIfAvailable() {
+  int64 monotonicTime;
+  int64 mediaStreamCounter;
+  int64 swapBufferCounter;
+
+  // TODO: Use glXGetMscRateOML (where available) to get the correct interval
+  // time. If unavailable, we should plumb-in information about when we
+  // clock down.
+  const int64 intervalTime = base::Time::kMicrosecondsPerSecond / 60;

[piman, 2012/10/24 16:56:54]

This sounds like it belongs to GLSurfaceGLX too.

[ajuma, 2012/10/26 20:12:39]

Done.

+
+  if (GetSyncValues(&monotonicTime, &mediaStreamCounter, &swapBufferCounter)) {
+    base::TimeTicks timebase = base::TimeTicks::FromInternalValue(
+        monotonicTime);
+    base::TimeDelta interval = base::TimeDelta::FromMicroseconds(intervalTime);
+    helper_->SendUpdateVSyncParameters(timebase, interval);
+  }
+}
+
 }  // namespace content
 
 #endif  // defined(ENABLE_GPU)