Enable creation of offscreen contexts which own their backing surface.

gpu/ipc/service/gpu_command_buffer_stub.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/ipc/service/gpu_command_buffer_stub.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 605 matching lines @@
                                       decoder_.get()));
   sync_point_client_ = channel_->sync_point_manager()->CreateSyncPointClient(
       channel_->GetSyncPointOrderData(stream_id_),
       CommandBufferNamespace::GPU_IO, command_buffer_id_);
 
   executor_->SetPreemptByFlag(channel_->preempted_flag());
 
   decoder_->set_engine(executor_.get());
 
   if (offscreen) {
-    surface_ = default_surface;
+    if (init_params.attribs.own_offscreen_surface) {
+      DVLOG(1) << __FUNCTION__ << "Hit the own_offscreen_surface path";
+      use_virtualized_gl_context_ = false;
+      // Currently, we always get alpha channe by default.

[dcheng, 2017/01/09 23:14:57]

Nit: channe => channel

[klausw, 2017/01/09 23:33:24]

Done, I've also reworded the comment a bit to be clearer.

+      // TODO(klausw): add way to disable alpha?
+      if (init_params.attribs.depth_size > 0) {
+        surface_format.SetDepthBits(init_params.attribs.depth_size);
+      }
+      if (init_params.attribs.samples > 0) {
+        surface_format.SetSamples(init_params.attribs.samples);
+      }
+      if (init_params.attribs.stencil_size > 0) {
+        surface_format.SetStencilBits(init_params.attribs.stencil_size);
+      }
+      surface_ = gl::init::CreateOffscreenGLSurfaceWithFormat(
+          gfx::Size(), surface_format);
+      if (!surface_) {
+        DLOG(ERROR) << "Failed to create surface.";
+        return false;
+      }
+    } else {
+      surface_ = default_surface;
+    }
   } else {
     surface_ = ImageTransportSurface::CreateNativeSurface(
         AsWeakPtr(), surface_handle_, surface_format);
     if (!surface_ || !surface_->Initialize(surface_format)) {
       surface_ = nullptr;
       DLOG(ERROR) << "Failed to create surface.";
       return false;
     }
   }
 
@@ skipping 565 matching lines @@
       command_buffer_->GetLastState().error == error::kLostContext)
     return;
 
   command_buffer_->SetContextLostReason(error::kUnknown);
   if (decoder_)
     decoder_->MarkContextLost(error::kUnknown);
   command_buffer_->SetParseError(error::kLostContext);
 }
 
 }  // namespace gpu