cc: Add threaded GPU rasterization.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 4ec16f2d177953a9ad1d950384084f77bfbe669a..a2e1064081b3803a7885edb4a7a74796ff1807cd 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -992,6 +992,7 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
     use_software = true;
 
   scoped_refptr<ContextProviderCommandBuffer> context_provider;
+  scoped_refptr<ContextProviderCommandBuffer> worker_context_provider;
   if (!use_software) {
     context_provider = ContextProviderCommandBuffer::Create(
         CreateGraphicsContext3D(), "RenderCompositor");
@@ -999,14 +1000,21 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
       // Cause the compositor to wait and try again.
       return scoped_ptr<cc::OutputSurface>();
     }
+
+    worker_context_provider = ContextProviderCommandBuffer::Create(
+        CreateGraphicsContext3D(), "RenderWorker");
+    if (!worker_context_provider.get()) {
+      // Cause the compositor to wait and try again.
+      return scoped_ptr<cc::OutputSurface>();
+    }
   }
 
   uint32 output_surface_id = next_output_surface_id_++;
   if (command_line.HasSwitch(switches::kEnableDelegatedRenderer)) {
     DCHECK(compositor_deps_->GetCompositorImplThreadTaskRunner());
     return scoped_ptr<cc::OutputSurface>(new DelegatedCompositorOutputSurface(
-        routing_id(), output_surface_id, context_provider, nullptr,
-        frame_swap_message_queue_));
+        routing_id(), output_surface_id, context_provider,
+        worker_context_provider, frame_swap_message_queue_));
   }
   if (!context_provider.get()) {
     scoped_ptr<cc::SoftwareOutputDevice> software_device(
@@ -1026,15 +1034,15 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
     if (base::SysInfo::IsLowEndDevice())
       format = cc::RGB_565;
     return scoped_ptr<cc::OutputSurface>(new MailboxOutputSurface(
-        routing_id(), output_surface_id, context_provider, nullptr,
-        scoped_ptr<cc::SoftwareOutputDevice>(), frame_swap_message_queue_,
-        format));
+        routing_id(), output_surface_id, context_provider,
+        worker_context_provider, scoped_ptr<cc::SoftwareOutputDevice>(),
+        frame_swap_message_queue_, format));
   }
   bool use_swap_compositor_frame_message = false;
   return scoped_ptr<cc::OutputSurface>(new CompositorOutputSurface(
-      routing_id(), output_surface_id, context_provider, nullptr,
-      scoped_ptr<cc::SoftwareOutputDevice>(), frame_swap_message_queue_,
-      use_swap_compositor_frame_message));
+      routing_id(), output_surface_id, context_provider,
+      worker_context_provider, scoped_ptr<cc::SoftwareOutputDevice>(),
+      frame_swap_message_queue_, use_swap_compositor_frame_message));
 }
 
 void RenderWidget::OnSwapBuffersAborted() {