Re-land: cc: Use worker context for one-copy tile initialization.

content/browser/compositor/gpu_process_transport_factory.cc

Index: content/browser/compositor/gpu_process_transport_factory.cc
diff --git a/content/browser/compositor/gpu_process_transport_factory.cc b/content/browser/compositor/gpu_process_transport_factory.cc
index a6d18220786b8454cdf8339c2d339b8b2b3c7a5f..2b3a52f0aa027e66e4076df6f5d08d8a41db8a06 100644
--- a/content/browser/compositor/gpu_process_transport_factory.cc
+++ b/content/browser/compositor/gpu_process_transport_factory.cc
@@ -263,6 +263,11 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
     }
   }
 
+  scoped_refptr<ContextProviderCommandBuffer> worker_context_provider(
+      ContextProviderCommandBuffer::Create(
+          GpuProcessTransportFactory::CreateOffscreenCommandBufferContext(),
+          BROWSER_WORKER_CONTEXT));

[piman, 2015/07/23 20:44:52]

Can you move this into the else block below, so that we don't try to do this if
we go software?

Separately, is there a way for us to share this context across compositors?
Since compositors typically don't go "invisible", we never really trim memory
for them (shm, command buffers etc.), so it would be good if we could share the
context to keep the memory footprint in check (avoid scaling with the number of
windows).

[reveman, 2015/07/24 17:49:15]

Done. Added a shared worker context provider to latest patch.

+
   scoped_ptr<BrowserCompositorOutputSurface> surface;
   if (!create_gpu_output_surface) {
     surface = make_scoped_ptr(new SoftwareBrowserCompositorOutputSurface(
@@ -279,12 +284,14 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
     } else if (capabilities.gpu.surfaceless) {
       surface =
           make_scoped_ptr(new GpuSurfacelessBrowserCompositorOutputSurface(
-              context_provider, data->surface_id, compositor->vsync_manager(),
+              context_provider, worker_context_provider, data->surface_id,
+              compositor->vsync_manager(),
               CreateOverlayCandidateValidator(compositor->widget()),
               GL_TEXTURE_2D, GL_RGB, BrowserGpuMemoryBufferManager::current()));
     } else {
       surface = make_scoped_ptr(new GpuBrowserCompositorOutputSurface(
-          context_provider, compositor->vsync_manager(),
+          context_provider, worker_context_provider,
+          compositor->vsync_manager(),
           CreateOverlayCandidateValidator(compositor->widget())));
     }
   }
@@ -314,7 +321,8 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
 
   scoped_ptr<cc::SurfaceDisplayOutputSurface> output_surface(
       new cc::SurfaceDisplayOutputSurface(
-          manager, compositor->surface_id_allocator(), context_provider));
+          manager, compositor->surface_id_allocator(), context_provider,
+          worker_context_provider));
   display_client->set_surface_output_surface(output_surface.get());
   output_surface->set_display_client(display_client.get());
   display_client->display()->Resize(compositor->size());