Unassociating MediaSession from media players (in blink & content)

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

-// 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.
-
-#include "modules/mediasession/HTMLMediaElementMediaSession.h"
-
-#include "core/dom/ExceptionCode.h"
-
-namespace blink {
-
-MediaSession* HTMLMediaElementMediaSession::session(HTMLMediaElement& mediaElement)
-{
-    if (HTMLMediaElementMediaSession* supplement = fromIfExists(mediaElement))
-        return supplement->m_session.get();
-    return nullptr;
-}
-
-void HTMLMediaElementMediaSession::setSession(HTMLMediaElement& mediaElement, MediaSession* session, ExceptionState& exceptionState)
-{
-    HTMLMediaElement::NetworkState networkState = mediaElement.getNetworkState();
-    if (networkState == HTMLMediaElement::kNetworkIdle || networkState == HTMLMediaElement::kNetworkLoading) {
-        exceptionState.throwDOMException(InvalidStateError, "networkState must be kNetworkEmpty or kNetworkNoSource.");
-        return;
-    }
-
-    from(mediaElement).m_session = session;
-}
-
-const char* HTMLMediaElementMediaSession::supplementName()
-{
-    return "HTMLMediaElementMediaSession";
-}
-
-HTMLMediaElementMediaSession& HTMLMediaElementMediaSession::from(HTMLMediaElement& element)
-{
-    HTMLMediaElementMediaSession* supplement = fromIfExists(element);
-    if (!supplement) {
-        supplement = new HTMLMediaElementMediaSession();
-        provideTo(element, supplementName(), supplement);
-    }
-    return *supplement;
-}
-
-HTMLMediaElementMediaSession* HTMLMediaElementMediaSession::fromIfExists(HTMLMediaElement& element)
-{
-    return static_cast<HTMLMediaElementMediaSession*>(Supplement<HTMLMediaElement>::from(element, supplementName()));
-}
-
-DEFINE_TRACE(HTMLMediaElementMediaSession)
-{
-    visitor->trace(m_session);
-    Supplement<HTMLMediaElement>::trace(visitor);
-}
-
-} // namespace blink