Implement MediaMetadata artwork in Blink

third_party/WebKit/public/platform/modules/mediasession/WebMediaArtwork.h

Index: third_party/WebKit/public/platform/modules/mediasession/WebMediaArtwork.h
diff --git a/third_party/WebKit/public/platform/modules/mediasession/WebMediaArtwork.h b/third_party/WebKit/public/platform/modules/mediasession/WebMediaArtwork.h
new file mode 100644
index 0000000000000000000000000000000000000000..fca376452dac434e6e4889344ff8e4f2bef26f34
--- /dev/null
+++ b/third_party/WebKit/public/platform/modules/mediasession/WebMediaArtwork.h
@@ -0,0 +1,21 @@
+// Copyright 2016 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 WebMediaArtwork_h
+#define WebMediaArtwork_h
+
+#include "public/platform/WebString.h"
+
+namespace blink {
+
+// Representation of MediaArtwork interface to the content layer.
+struct WebMediaArtwork {
+    WebString src;
+    WebString sizes;
+    WebString type;
+};
+
+}
+
+#endif // WebMediaArtwork_h