Implement MediaSession (metadata) per frame [NOT READY, HAS DEPENDENCY]

third_party/WebKit/Source/modules/mediasession/NavigatorMediaSession.cpp

Index: third_party/WebKit/Source/modules/mediasession/NavigatorMediaSession.cpp
diff --git a/third_party/WebKit/Source/modules/mediasession/NavigatorMediaSession.cpp b/third_party/WebKit/Source/modules/mediasession/NavigatorMediaSession.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..efdcd34c636b02789b08d3f837a74a5f5b3f3020
--- /dev/null
+++ b/third_party/WebKit/Source/modules/mediasession/NavigatorMediaSession.cpp
@@ -0,0 +1,47 @@
+// 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.
+
+#include "modules/mediasession/NavigatorMediaSession.h"
+
+#include "bindings/core/v8/ExceptionStatePlaceholder.h"
+#include "modules/mediasession/MediaSession.h"
+#include "platform/Supplementable.h"
+
+namespace blink {
+
+NavigatorMediaSession::NavigatorMediaSession(Navigator& navigator)
+    : DOMWindowProperty(navigator.frame())
+{
+    if (!frame())
+        return;
+    m_session = MediaSession::create(frame(), IGNORE_EXCEPTION);
+}
+
+DEFINE_TRACE(NavigatorMediaSession)
+{
+    visitor->trace(m_session);
+    Supplement<Navigator>::trace(visitor);
+    DOMWindowProperty::trace(visitor);
+}
+
+const char* NavigatorMediaSession::supplementName()
+{
+    return "NavigatorMediaSession";
+}
+
+NavigatorMediaSession& NavigatorMediaSession::from(Navigator& navigator)
+{
+    NavigatorMediaSession* supplement = static_cast<NavigatorMediaSession*>(Supplement<Navigator>::from(navigator, supplementName()));
+    if (!supplement) {
+        supplement = new NavigatorMediaSession(navigator);
+        provideTo(navigator, supplementName(), supplement);
+    }
+    return *supplement;
+}
+
+MediaSession* NavigatorMediaSession::mediaSession(Navigator& navigator)
+{
+    return NavigatorMediaSession::from(navigator).m_session.get();
+}
+}