cc: Implement shared worker contexts.

content/common/gpu/client/context_provider_command_buffer.h

 // Copyright (c) 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_COMMON_GPU_CLIENT_CONTEXT_PROVIDER_COMMAND_BUFFER_H_
 #define CONTENT_COMMON_GPU_CLIENT_CONTEXT_PROVIDER_COMMAND_BUFFER_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
@@ skipping 12 matching lines @@
 // WebGraphicsContext3DCommandBufferImpl context and a GrContext.
 class CONTENT_EXPORT ContextProviderCommandBuffer
     : NON_EXPORTED_BASE(public cc_blink::ContextProviderWebContext) {
  public:
   static scoped_refptr<ContextProviderCommandBuffer> Create(
       scoped_ptr<WebGraphicsContext3DCommandBufferImpl> context3d,
       CommandBufferContextType type);
 
   CommandBufferProxyImpl* GetCommandBufferProxy();
 
+  // Force the command buffer to be torn down as if the context was lost. The
+  // context can still be used just like in lost context situations but it is
+  // no longer bound to a specific thread so it is safe for the previously
+  // bound thread to drop any reference it has. This should only be used if
+  // content provider has been set up for multi-threaded usage by calling
+  // SetupLock().
+  void Destroy();
+
   // cc_blink::ContextProviderWebContext implementation.
   WebGraphicsContext3DCommandBufferImpl* WebContext3D() override;
 
   // cc::ContextProvider implementation.
   bool BindToCurrentThread() override;
   void DetachFromThread() override;
   gpu::gles2::GLES2Interface* ContextGL() override;
   gpu::ContextSupport* ContextSupport() override;
   class GrContext* GrContext() override;
   void InvalidateGrContext(uint32_t state) override;
@@ skipping 13 matching lines @@
   ContextProviderCommandBuffer(
       scoped_ptr<WebGraphicsContext3DCommandBufferImpl> context3d,
       CommandBufferContextType type);
   ~ContextProviderCommandBuffer() override;
 
   void OnLostContext();
   void OnMemoryAllocationChanged(const gpu::MemoryAllocation& allocation);
 
  private:
   void InitializeCapabilities();
+  void DestroyWithMainThreadLockAcquired();
 
   base::ThreadChecker main_thread_checker_;
   base::ThreadChecker context_thread_checker_;
 
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> context3d_;
   scoped_ptr<GrContextForWebGraphicsContext3D> gr_context_;
 
   cc::ContextProvider::Capabilities capabilities_;
   CommandBufferContextType context_type_;
   std::string debug_name_;
 
   LostContextCallback lost_context_callback_;
   MemoryPolicyChangedCallback memory_policy_changed_callback_;
 
   base::Lock main_thread_lock_;
   bool destroyed_;
 
   base::Lock context_lock_;
 
   class LostContextCallbackProxy;
   scoped_ptr<LostContextCallbackProxy> lost_context_callback_proxy_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_CONTEXT_PROVIDER_COMMAND_BUFFER_H_