Media Capabilities: add plumbing between Blink and media/blink/.

third_party/WebKit/public/platform/modules/media_capabilities/WebMediaCapabilitiesClient.h

+// Copyright 2017 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 WebMediaCapabilitiesClient_h
+#define WebMediaCapabilitiesClient_h
+
+#include <memory>
+
+#include "public/platform/modules/media_capabilities/WebMediaDecodingAbility.h"
+
+namespace blink {
+
+struct WebMediaConfiguration;
+
+// Interface between Blink and the Media layer.
+class WebMediaCapabilitiesClient {
+ public:
+  virtual ~WebMediaCapabilitiesClient() = default;
+
+  virtual void query(const WebMediaConfiguration&,
+                     std::unique_ptr<WebMediaCapabilitiesQueryCallbacks>) = 0;
+};
+
+}  // namespace blink
+
+#endif  // WebMediaCapabilitiesClient_h