Ozone: Avoid blocking in Swapbuffer Call.

content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc

Index: content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
diff --git a/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc b/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
index 0245aae7059df70b1807785b464e4e21188d78e8..819a23026f7c25bd5bbabaab0ebf7584c2035693 100644
--- a/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
+++ b/content/browser/compositor/gpu_surfaceless_browser_compositor_output_surface.cc
@@ -30,7 +30,10 @@ GpuSurfacelessBrowserCompositorOutputSurface::
                                         vsync_manager,
                                         overlay_candidate_validator.Pass()),
       internalformat_(internalformat),
-      use_own_gl_helper_(use_own_gl_helper) {
+      use_own_gl_helper_(use_own_gl_helper),
+      page_flip_completion_callback_(
+          base::Bind(&GpuSurfacelessBrowserCompositorOutputSurface::
+              OnPageFlipCompleted, base::Unretained(this))) {
   capabilities_.uses_default_gl_framebuffer = false;
   capabilities_.flipped_output_surface = true;
 }
@@ -63,7 +66,6 @@ void GpuSurfacelessBrowserCompositorOutputSurface::SwapBuffers(
 
 void GpuSurfacelessBrowserCompositorOutputSurface::OnSwapBuffersComplete() {
   DCHECK(output_surface_);
-  output_surface_->PageFlipComplete();
   GpuBrowserCompositorOutputSurface::OnSwapBuffersComplete();
 }
 
@@ -97,7 +99,15 @@ bool GpuSurfacelessBrowserCompositorOutputSurface::BindToClient(
 
   output_surface_.reset(
       new BufferQueue(context_provider_, internalformat_, helper));
+
+  GetCommandBufferProxy()->SetPageFlipCompletionCallback(
+      page_flip_completion_callback_.callback());

[alexst (slow to review), 2014/12/10 23:19:25]

Why not base::Bind(&BufferQueue::PageFlipComplete,
base::Unretained(output_surface_.get())) here instead?

[kalyank, 2014/12/11 12:55:58]

Done.

+
   return output_surface_->Initialize();
 }
 
+void GpuSurfacelessBrowserCompositorOutputSurface::OnPageFlipCompleted() {
+  output_surface_->PageFlipComplete();
+}
+
 }  // namespace content