gpu: Add flag for enabling asynchronous worker context.

content/browser/gpu/compositor_util.h

 // Copyright 2013 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_BROWSER_GPU_COMPOSITOR_UTIL_H_
 #define CONTENT_BROWSER_GPU_COMPOSITOR_UTIL_H_
 
 #include "base/values.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // Note: When adding a function here, please make sure the logic is not
 // duplicated in the renderer.
 
 // Returns true if zero-copy uploads is on (via flags, or platform default).
 // Only one of one-copy and zero-copy can be enabled at a time.
 CONTENT_EXPORT bool IsZeroCopyUploadEnabled();
 
 // Returns true if a partial raster is on (via flags).
 CONTENT_EXPORT bool IsPartialRasterEnabled();
 
 // Returns true if all compositor resources should use GPU memory buffers.
 CONTENT_EXPORT bool IsGpuMemoryBufferCompositorResourcesEnabled();
 
 // Returns true if gpu rasterization is on (via flags) for the renderer.
 CONTENT_EXPORT bool IsGpuRasterizationEnabled();
 
+// returns true if async worker context is on (via flags).
+CONTENT_EXPORT bool IsAsyncWorkerContextEnabled();
+
 // Returns the number of multisample antialiasing samples (via flags) for
 // GPU rasterization.
 CONTENT_EXPORT int GpuRasterizationMSAASampleCount();
 
 // Returns true if force-gpu-rasterization is on (via flags) for the renderer.
 CONTENT_EXPORT bool IsForceGpuRasterizationEnabled();
 
 // Returns the number of raster threads to use for compositing.
 CONTENT_EXPORT int NumberOfRendererRasterThreads();
 
 CONTENT_EXPORT base::DictionaryValue* GetFeatureStatus();
 CONTENT_EXPORT base::Value* GetProblems();
 CONTENT_EXPORT std::vector<std::string> GetDriverBugWorkarounds();
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_COMPOSITOR_UTIL_H_