Remove base::Callback from ContextProvider creation.

content/common/gpu/client/context_provider_command_buffer.h

Index: content/common/gpu/client/context_provider_command_buffer.h
diff --git a/content/common/gpu/client/context_provider_command_buffer.h b/content/common/gpu/client/context_provider_command_buffer.h
index 1b0e92eb9bee577188e465a1a8e0ccab18d6ce57..efaf87a3c18bcea0860c117c6e405a4043125719 100644
--- a/content/common/gpu/client/context_provider_command_buffer.h
+++ b/content/common/gpu/client/context_provider_command_buffer.h
@@ -23,10 +23,8 @@ namespace content {
 // WebGraphicsContext3DCommandBufferImpl context and a GrContext.
 class ContextProviderCommandBuffer : public cc::ContextProvider {
  public:
-  typedef base::Callback<
-      scoped_ptr<WebGraphicsContext3DCommandBufferImpl>(void)> CreateCallback;
   static scoped_refptr<ContextProviderCommandBuffer> Create(
-      const CreateCallback& create_callback);
+      scoped_ptr<WebGraphicsContext3DCommandBufferImpl> context3d);
 
   virtual bool BindToCurrentThread() OVERRIDE;
   virtual WebGraphicsContext3DCommandBufferImpl* Context3d() OVERRIDE;
@@ -48,13 +46,10 @@ class ContextProviderCommandBuffer : public cc::ContextProvider {
   }
 
  protected:
-  ContextProviderCommandBuffer();
+  ContextProviderCommandBuffer(
+      scoped_ptr<WebGraphicsContext3DCommandBufferImpl> context3d);
   virtual ~ContextProviderCommandBuffer();
 
-  // This must be called immedately after creating this object, and it should
-  // be thrown away if this returns false.
-  bool InitializeOnMainThread(const CreateCallback& create_callback);
-
   void OnLostContext();
   void OnSwapBuffersComplete();
   void OnMemoryAllocationChanged(