content: Pass surfacelessness of GL context from GPU to browser

Currently we rely on a flag (--ozone-use-surfaceless) to trigger the
surfaceless code path in both GPU & browser processes.

This makes surfacelessness a context capability, so that we can create
the appropriate output surface in the browser without using the flag.

BUG=512631
TEST=Manually on link. UI is drawn.

Review URL: https://codereview.chromium.org/1243263002

Cr-Commit-Position: refs/heads/master@{#339821}

content/browser/compositor/gpu_process_transport_factory.cc

@@ -270,23 +270,19 @@ void GpuProcessTransportFactory::EstablishedGpuChannel(
         compositor->vsync_manager()));
   } else {
     DCHECK(context_provider);
+    ContextProvider::Capabilities capabilities =
+        context_provider->ContextCapabilities();
     if (!data->surface_id) {
       surface = make_scoped_ptr(new OffscreenBrowserCompositorOutputSurface(
           context_provider, compositor->vsync_manager(),
           scoped_ptr<BrowserCompositorOverlayCandidateValidator>()));
-    } else
-#if defined(USE_OZONE)
-        if (ui::OzonePlatform::GetInstance()
-                ->GetOverlayManager()
-                ->CanShowPrimaryPlaneAsOverlay()) {
+    } else if (capabilities.gpu.surfaceless) {
       surface =
           make_scoped_ptr(new GpuSurfacelessBrowserCompositorOutputSurface(
               context_provider, data->surface_id, compositor->vsync_manager(),
               CreateOverlayCandidateValidator(compositor->widget()), GL_RGB,
               BrowserGpuMemoryBufferManager::current()));
-    } else
-#endif
-    {
+    } else {
       surface = make_scoped_ptr(new GpuBrowserCompositorOutputSurface(
           context_provider, compositor->vsync_manager(),
           CreateOverlayCandidateValidator(compositor->widget())));

gpu/command_buffer/common/capabilities.cc

@@ -75,6 +75,7 @@ Capabilities::Capabilities()
       texture_rg(false),
       render_buffer_format_bgra8888(false),
       occlusion_query_boolean(false),
+      surfaceless(false),
       major_version(2),
       minor_version(0) {
 }

gpu/command_buffer/common/capabilities.h

@@ -135,6 +135,7 @@ struct GPU_EXPORT Capabilities {
   bool render_buffer_format_bgra8888;
   bool occlusion_query_boolean;
   bool timer_queries;
+  bool surfaceless;
 
   int major_version;
   int minor_version;

gpu/command_buffer/service/gles2_cmd_decoder.cc

@@ -3145,6 +3145,7 @@ Capabilities GLES2DecoderImpl::GetCapabilities() {
 
   caps.post_sub_buffer = supports_post_sub_buffer_;
   caps.image = true;
+  caps.surfaceless = surfaceless_;
 
   caps.blend_equation_advanced =
       feature_info_->feature_flags().blend_equation_advanced;

gpu/ipc/gpu_command_buffer_traits_multi.h

@@ -97,6 +97,7 @@ IPC_STRUCT_TRAITS_BEGIN(gpu::Capabilities)
   IPC_STRUCT_TRAITS_MEMBER(render_buffer_format_bgra8888)
   IPC_STRUCT_TRAITS_MEMBER(occlusion_query_boolean)
   IPC_STRUCT_TRAITS_MEMBER(timer_queries)
+  IPC_STRUCT_TRAITS_MEMBER(surfaceless)
 
   IPC_STRUCT_TRAITS_MEMBER(major_version)
   IPC_STRUCT_TRAITS_MEMBER(minor_version)