Update from https://crrev.com/315085

cc/blink/context_provider_web_context.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 CC_BLINK_CONTEXT_PROVIDER_WEB_CONTEXT_H_
+#define CC_BLINK_CONTEXT_PROVIDER_WEB_CONTEXT_H_
+
+#include "cc/output/context_provider.h"
+
+namespace blink { class WebGraphicsContext3D; }
+
+namespace cc_blink {
+
+class ContextProviderWebContext : public cc::ContextProvider {
+ public:
+  virtual blink::WebGraphicsContext3D* WebContext3D() = 0;
+
+ protected:
+  ~ContextProviderWebContext() override {}
+};
+
+}  // namespace cc_blink
+
+#endif  // CC_BLINK_CONTEXT_PROVIDER_WEB_CONTEXT_H_