Add a JS API for detecting WebGL availability.

content/browser/gpu/gpu_data_manager.h

 // Copyright (c) 2011 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_GPU_DATA_MANAGER_H_
 #define CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_H_
 #pragma once
 
 #include <set>
 #include <string>
@@ skipping 29 matching lines @@
   static GpuDataManager* GetInstance();
 
   // Requests complete GPUinfo if it has not already been requested
   void RequestCompleteGpuInfoIfNeeded();
 
   // Only update if the current GPUInfo is not finalized.
   void UpdateGpuInfo(const content::GPUInfo& gpu_info);
 
   const content::GPUInfo& gpu_info() const;
 
+  bool complete_gpu_info_available() const {
+    return complete_gpu_info_available_;
+  }
+
   // Returns status of various GPU features. This is two parted:
   // {
   //    featureStatus: []
   //    problems: []
   // }
   //
   // Each entry in feature_status has:
   // {
   //    name:  "name of feature"
   //    status: "enabled" | "unavailable_software" | "unavailable_off" |
@@ skipping 155 matching lines @@
   static bool Merge(content::GPUInfo* object, const content::GPUInfo& other);
 
   // Determin if accelerated-2d-canvas is supported, which depends on whether
   // lose_context could happen and whether skia is the backend.
   bool supportsAccelerated2dCanvas() const;
 
   // Try to switch to software rendering, if possible and necessary.
   void EnableSoftwareRenderingIfNecessary();
 
   bool complete_gpu_info_already_requested_;
+  bool complete_gpu_info_available_;

[Ken Russell (switch to Gerrit), 2011/12/03 02:59:42]

I don't fully understand the threading model in this code, but is this variable
written and tested by different threads?

 
   GpuFeatureFlags gpu_feature_flags_;
   GpuFeatureFlags preliminary_gpu_feature_flags_;
 
   UserFlags user_flags_;
 
   content::GPUInfo gpu_info_;
   mutable base::Lock gpu_info_lock_;
 
   scoped_ptr<GpuBlacklist> gpu_blacklist_;
 
   // Observers.
   const scoped_refptr<GpuDataManagerObserverList> observer_list_;
 
   ListValue log_messages_;
   bool software_rendering_;
 
   FilePath swiftshader_path_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuDataManager);
 };
 
 #endif  // CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_H_