services/ui: Use a gpu::GpuChannelHost when creating ui::OutputSurface.

services/ui/demo/bitmap_uploader.cc

 // Copyright 2015 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 "services/ui/demo/bitmap_uploader.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "cc/ipc/compositor_frame.mojom.h"
 #include "cc/quads/render_pass.h"
 #include "cc/quads/solid_color_draw_quad.h"
 #include "cc/quads/texture_draw_quad.h"
 #include "services/ui/public/cpp/gles2_context.h"
+#include "services/ui/public/cpp/gpu_service.h"
 #include "services/ui/public/cpp/window.h"
 #include "services/ui/public/cpp/window_surface.h"
 
 namespace ui {
 namespace {
 
 const uint32_t g_transparent_color = 0x00000000;
 
 }  // namespace
 
 const char kBitmapUploaderForAcceleratedWidget[] =
     "__BITMAP_UPLOADER_ACCELERATED_WIDGET__";
 
 BitmapUploader::BitmapUploader(Window* window, GpuService* gpu_service)
     : window_(window),
-      gpu_service_(gpu_service),
       color_(g_transparent_color),
       width_(0),
       height_(0),
       format_(BGRA),
-      next_resource_id_(1u) {}
-
-BitmapUploader::~BitmapUploader() {
-}
-
-void BitmapUploader::Init() {
+      next_resource_id_(1u) {
   surface_ = window_->RequestSurface(mojom::SurfaceType::DEFAULT);
   surface_->BindToThread();
   surface_->set_client(this);
 
-  gles2_context_ = GLES2Context::CreateOffscreenContext(gpu_service_);
+  gles2_context_ = GLES2Context::CreateOffscreenContext(
+      gpu_service->EstablishGpuChannelSync());

[sky, 2016/08/18 13:15:45]

Aren't these all rather expensive calls? Seems like an Init() better matches the
style guide.

[sadrul, 2016/08/18 14:59:48]

Done.

   // CreateOffscreenContext() may return null.

[sky, 2016/08/18 13:15:45]

Update or remove comment?

[sadrul, 2016/08/18 14:59:48]

Done (removed)

 }
 
+BitmapUploader::~BitmapUploader() {}
+
 // Sets the color which is RGBA.
 void BitmapUploader::SetColor(uint32_t color) {
   if (color_ == color)
     return;
   color_ = color;
   if (surface_)
     Upload();
 }
 
 // Sets a bitmap.
@@ skipping 133 matching lines @@
     DCHECK_EQ(1, resource.count);
     gl->WaitSyncTokenCHROMIUM(resource.sync_token.GetConstData());
     uint32_t texture_id = resource_to_texture_id_map_[resource.id];
     DCHECK_NE(0u, texture_id);
     resource_to_texture_id_map_.erase(resource.id);
     gl->DeleteTextures(1, &texture_id);
   }
 }
 
 }  // namespace ui