zero-copy: Clarify to allocate/destroy GpuMemoryBuffer on any thread and use it on the main thread o

ui/ozone/platform/drm/drm_surface_factory.cc

 // Copyright 2014 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 "ui/ozone/platform/drm/drm_surface_factory.h"
 
 #include <errno.h>
 
 #include "ui/gfx/native_widget_types.h"
 #include "ui/ozone/platform/drm/gpu/drm_surface.h"
 #include "ui/ozone/platform/drm/gpu/drm_util.h"
 #include "ui/ozone/platform/drm/gpu/drm_window.h"
 #include "ui/ozone/platform/drm/gpu/hardware_display_controller.h"
 #include "ui/ozone/platform/drm/gpu/screen_manager.h"
 #include "ui/ozone/public/surface_ozone_canvas.h"
 
 namespace ui {
 
 DrmSurfaceFactory::DrmSurfaceFactory(ScreenManager* screen_manager)
     : screen_manager_(screen_manager) {
 }
 
 DrmSurfaceFactory::~DrmSurfaceFactory() {
 }
 
 scoped_ptr<ui::SurfaceOzoneCanvas> DrmSurfaceFactory::CreateCanvasForWidget(
     gfx::AcceleratedWidget widget) {
+  DCHECK(thread_checker_.CalledOnValidThread());

[reveman, 2015/04/07 13:07:05]

ditto. how is this related?

   return make_scoped_ptr(new DrmSurface(screen_manager_->GetWindow(widget)));
 }
 
 bool DrmSurfaceFactory::LoadEGLGLES2Bindings(
     AddGLLibraryCallback add_gl_library,
     SetGLGetProcAddressProcCallback set_gl_get_proc_address) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   return false;
 }
 
 }  // namespace ui