Make lost context callback a base::Closure thru the WGC3DProvider.

content/renderer/webgraphicscontext3d_provider_impl.h

 // Copyright 2014 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_RENDERER_WEBGRAPHICSCONTEXT3D_PROVIDER_IMPL_H_
 #define CONTENT_RENDERER_WEBGRAPHICSCONTEXT3D_PROVIDER_IMPL_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
@@ skipping 15 matching lines @@
     : public NON_EXPORTED_BASE(blink::WebGraphicsContext3DProvider) {
  public:
   explicit WebGraphicsContext3DProviderImpl(
       scoped_refptr<cc_blink::ContextProviderWebContext> provider);
   ~WebGraphicsContext3DProviderImpl() override;
 
   // WebGraphicsContext3DProvider implementation.
   blink::WebGraphicsContext3D* context3d() override;
   gpu::gles2::GLES2Interface* contextGL() override;
   GrContext* grContext() override;
+  void setLostContextCallback(blink::WebClosure) override;
 
  private:
   scoped_refptr<cc_blink::ContextProviderWebContext> provider_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_WEBGRAPHICSCONTEXT3D_PROVIDER_IMPL_H_