Introduce WebMediaSession

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

Index: third_party/WebKit/public/platform/modules/mediasession/WebMediaSession.h
diff --git a/third_party/WebKit/public/platform/modules/mediasession/WebMediaSession.h b/third_party/WebKit/public/platform/modules/mediasession/WebMediaSession.h
new file mode 100644
index 0000000000000000000000000000000000000000..7a3c67770a927a608eb06fa58ce251749b2cfa03
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+++ b/third_party/WebKit/public/platform/modules/mediasession/WebMediaSession.h
@@ -0,0 +1,25 @@
+// Copyright 2015 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 WebMediaSession_h
+#define WebMediaSession_h
+
+#include "public/platform/WebCallbacks.h"
+#include "public/platform/modules/mediasession/WebMediaSessionError.h"
+
+namespace blink {
+
+using WebMediaSessionCommandCallback = WebCallbacks<void, const WebMediaSessionError&>;
+
+class WebMediaSession {
+public:
+    virtual ~WebMediaSession() = default;
+
+    virtual void activate(WebMediaSessionCommandCallback*) = 0;
+    virtual void deactivate(WebMediaSessionCommandCallback*) = 0;
+};
+
+} // namespace blink
+
+#endif // WebMediaSession_h