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 47bb204d7d225474af46f82affacd7ae222385f9..de566748e97ec0c65303b1386e87c0f72ce1e15a 100644
--- a/content/common/gpu/image_transport_surface.cc
+++ b/content/common/gpu/image_transport_surface.cc
@@ -157,6 +157,13 @@ void ImageTransportHelper::SendResizeView(const gfx::Size& size) {
                                            size));
 }
 
+void ImageTransportHelper::SendUpdateVSyncParameters(
+      base::TimeTicks timebase, base::TimeDelta interval) {
+  manager_->Send(new GpuHostMsg_UpdateVSyncParameters(stub_->surface_id(),
+                                                      timebase,
+                                                      interval));
+}
+
 void ImageTransportHelper::SetScheduled(bool is_scheduled) {
   gpu::GpuScheduler* scheduler = Scheduler();
   if (!scheduler)
@@ -271,6 +278,7 @@ 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
@@ -287,6 +295,7 @@ 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
@@ -343,6 +352,18 @@ gfx::Size PassThroughImageTransportSurface::GetSize() {
 
 PassThroughImageTransportSurface::~PassThroughImageTransportSurface() {}
 
+void PassThroughImageTransportSurface::SendVSyncUpdateIfAvailable() {
+// TODO (ajuma): Fix up the browser-side handling of these updates on
+// non-Aura, so we can remove this ifdef.
+#if defined(USE_AURA)

[piman, 2012/10/29 20:36:39]

No ifdef AURA in the GPU-process code. Aura is a UI-concept and shouldn't leak
here.
Possibly what you mean is to check whether this surface is a "transport" one
(i.e. representing a renderer), or not?

[ajuma, 2012/10/30 21:04:04]

I've removed the ifdef. It turns out that not much code is needed to add support
for the desktop Linux case (to handle the message in the browser and forward the
vsync parameters to the appropriate renderer), so I've added this code in
GpuProcessHostUIShim.

+  base::TimeTicks timebase;
+  base::TimeDelta interval;
+  if (GetVSyncParameters(&timebase, &interval)) {
+    helper_->SendUpdateVSyncParameters(timebase, interval);
+  }
+#endif
+}
+
 }  // namespace content
 
 #endif  // defined(ENABLE_GPU)