aura: Allow in process ContextProvider to hold onscreen contexts.

webkit/common/gpu/context_provider_in_process.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 WEBKIT_COMMON_GPU_CONTEXT_PROVIDER_IN_PROCESS_H_
 #define WEBKIT_COMMON_GPU_CONTEXT_PROVIDER_IN_PROCESS_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "cc/output/context_provider.h"
 #include "webkit/common/gpu/webkit_gpu_export.h"
 
 namespace WebKit {
 class WebGraphicsContext3D;
 }
 
 namespace webkit {
 namespace gpu {
 class GrContextForWebGraphicsContext3D;
+class WebGraphicsContext3DInProcessCommandBufferImpl;
 
 class WEBKIT_GPU_EXPORT ContextProviderInProcess
     : NON_EXPORTED_BASE(public cc::ContextProvider) {
  public:
-  static scoped_refptr<ContextProviderInProcess> Create() {
-    scoped_refptr<ContextProviderInProcess> provider =
-        new ContextProviderInProcess;
-    if (!provider->InitializeOnMainThread())
-      return NULL;
-    return provider;
-  }
+  typedef base::Callback<
+      scoped_ptr<WebGraphicsContext3DInProcessCommandBufferImpl>(void)>
+      CreateCallback;
+
+  static scoped_refptr<ContextProviderInProcess> Create(
+      const CreateCallback& create_callback);
+
+  // Calls Create() with a default factory method for creating an offscreen
+  // context.
+  static scoped_refptr<ContextProviderInProcess> CreateOffscreen();
 
   virtual bool BindToCurrentThread() OVERRIDE;
   virtual WebKit::WebGraphicsContext3D* Context3d() OVERRIDE;
   virtual class GrContext* GrContext() OVERRIDE;
   virtual void VerifyContexts() OVERRIDE;
   virtual bool DestroyedOnMainThread() OVERRIDE;
   virtual void SetLostContextCallback(
       const LostContextCallback& lost_context_callback) OVERRIDE;
 
  protected:
   ContextProviderInProcess();
   virtual ~ContextProviderInProcess();
 
-  bool InitializeOnMainThread();
+  bool InitializeOnMainThread(
+      const CreateCallback& create_callback);
 
   void OnLostContext();
   void OnMemoryAllocationChanged(bool nonzero_allocation);
 
  private:
   base::ThreadChecker main_thread_checker_;
   base::ThreadChecker context_thread_checker_;
 
   scoped_ptr<WebKit::WebGraphicsContext3D> context3d_;
   scoped_ptr<webkit::gpu::GrContextForWebGraphicsContext3D> gr_context_;
 
   LostContextCallback lost_context_callback_;
 
   base::Lock destroyed_lock_;
   bool destroyed_;
 
   class LostContextCallbackProxy;
   scoped_ptr<LostContextCallbackProxy> lost_context_callback_proxy_;
 
   class MemoryAllocationCallbackProxy;
   scoped_ptr<MemoryAllocationCallbackProxy> memory_allocation_callback_proxy_;
 };
 
 }  // namespace gpu
 }  // namespace webkit
 
 #endif  // WEBKIT_COMMON_GPU_CONTEXT_PROVIDER_IN_PROCESS_H_