Plumb the partial swap though image transport.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 62b1d27e6375d47a86366c894f084b756cfb5b75..3dbf57247d50b9bdc051636cb38e5d847f663490 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -277,8 +277,8 @@ void RenderWidgetHostViewAura::OnAcceleratedCompositingStateChange() {
 }
 
 void RenderWidgetHostViewAura::AcceleratedSurfaceBuffersSwapped(
-      const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params,
-      int gpu_host_id) {
+    const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params,
+    int gpu_host_id) {
 #if defined(UI_COMPOSITOR_IMAGE_TRANSPORT)
   window_->layer()->SetExternalTexture(
       accelerated_surface_containers_[params.surface_id]->GetTexture());
@@ -287,14 +287,44 @@ void RenderWidgetHostViewAura::AcceleratedSurfaceBuffersSwapped(
   if (!window_->layer()->GetCompositor()) {
     // We have no compositor, so we have no way to display the surface.
     // Must still send the ACK.
-    host_->AcknowledgeSwapBuffers(params.route_id, gpu_host_id);
+    RenderWidgetHost::AcknowledgeSwapBuffers(params.route_id, gpu_host_id);
   } else {
     window_->layer()->ScheduleDraw();
 
     // Add sending an ACK to the list of things to do OnCompositingEnded
     on_compositing_ended_callbacks_.push_back(
         base::Bind(&RenderWidgetHost::AcknowledgeSwapBuffers,
-                   base::Unretained(host_), params.route_id, gpu_host_id));
+                   params.route_id, gpu_host_id));
+    ui::Compositor* compositor = window_->layer()->GetCompositor();
+    if (!compositor->HasObserver(this))
+      compositor->AddObserver(this);
+  }
+#else
+  NOTREACHED();
+#endif
+}
+
+void RenderWidgetHostViewAura::AcceleratedSurfacePostSubBuffer(
+    const GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params& params,
+    int gpu_host_id) {
+#if defined(UI_COMPOSITOR_IMAGE_TRANSPORT)
+  window_->layer()->SetExternalTexture(
+      accelerated_surface_containers_[params.surface_id]->GetTexture());
+  glFlush();
+
+  if (!window_->layer()->GetCompositor()) {
+    // We have no compositor, so we have no way to display the surface
+    // Must still send the ACK
+    RenderWidgetHost::AcknowledgePostSubBuffer(params.route_id, gpu_host_id);
+  } else {
+    // TODO(backer): Plumb the damage rect to the ui compositor so that we
+    // can do a partial swap to display.
+    window_->layer()->ScheduleDraw();
+
+    // Add sending an ACK to the list of things to do OnCompositingEnded
+    on_compositing_ended_callbacks_.push_back(
+        base::Bind(&RenderWidgetHost::AcknowledgePostSubBuffer,
+                   params.route_id, gpu_host_id));
     ui::Compositor* compositor = window_->layer()->GetCompositor();
     if (!compositor->HasObserver(this))
       compositor->AddObserver(this);