gpu: Add flag for enabling asynchronous worker context.

content/renderer/render_thread_impl.h

 // 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.
 
 #ifndef CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 #define CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 178 matching lines @@
       int64_t idle_notification_delay_in_ms) override;
   void UpdateHistograms(int sequence_number) override;
   int PostTaskToAllWebWorkers(const base::Closure& closure) override;
   bool ResolveProxy(const GURL& url, std::string* proxy_list) override;
   base::WaitableEvent* GetShutdownEvent() override;
   ServiceRegistry* GetServiceRegistry() override;
 
   // CompositorDependencies implementation.
   bool IsGpuRasterizationForced() override;
   bool IsGpuRasterizationEnabled() override;
+  bool IsAsyncWorkerContextEnabled() override;
   int GetGpuRasterizationMSAASampleCount() override;
   bool IsLcdTextEnabled() override;
   bool IsDistanceFieldTextEnabled() override;
   bool IsZeroCopyEnabled() override;
   bool IsPartialRasterEnabled() override;
   bool IsGpuMemoryBufferCompositorResourcesEnabled() override;
   bool IsElasticOverscrollEnabled() override;
   std::vector<unsigned> GetImageTextureTargets() override;
   scoped_refptr<base::SingleThreadTaskRunner>
   GetCompositorMainThreadTaskRunner() override;
@@ skipping 438 matching lines @@
 #endif
 
   std::unique_ptr<MemoryObserver> memory_observer_;
 
   scoped_refptr<base::SingleThreadTaskRunner>
       main_thread_compositor_task_runner_;
 
   // Compositor settings.
   bool is_gpu_rasterization_enabled_;
   bool is_gpu_rasterization_forced_;
+  bool is_async_worker_context_enabled_;
   int gpu_rasterization_msaa_sample_count_;
   bool is_lcd_text_enabled_;
   bool is_distance_field_text_enabled_;
   bool is_zero_copy_enabled_;
   bool is_gpu_memory_buffer_compositor_resources_enabled_;
   bool is_partial_raster_enabled_;
   bool is_elastic_overscroll_enabled_;
   std::vector<unsigned> use_image_texture_targets_;
   std::vector<unsigned> use_video_frame_image_texture_targets_;
   bool are_image_decode_tasks_enabled_;
@@ skipping 35 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 #if defined(COMPILER_MSVC)
 #pragma warning(pop)
 #endif
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_