Media Session API: make MediaMetadata mutable.

third_party/WebKit/Source/modules/mediasession/MediaSession.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/MediaSession.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/DocumentUserGestureToken.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/events/Event.h"
@@ skipping 62 matching lines @@
 
 MediaSession* MediaSession::create(ExecutionContext* executionContext) {
   return new MediaSession(executionContext);
 }
 
 void MediaSession::dispose() {
   m_clientBinding.Close();
 }
 
 void MediaSession::setMetadata(MediaMetadata* metadata) {
-  if (mojom::blink::MediaSessionService* service = getService()) {
-    service->SetMetadata(MediaMetadataSanitizer::sanitizeAndConvertToMojo(
-        metadata, getExecutionContext()));
-  }
+  if (metadata)
+    metadata->setSession(this);
+
+  if (m_metadata)
+    m_metadata->setSession(nullptr);
+
+  m_metadata = metadata;
+  onMetadataChanged();
 }
 
 MediaMetadata* MediaSession::metadata() const {
   return m_metadata;
 }
 
+void MediaSession::onMetadataChanged() {
+  mojom::blink::MediaSessionService* service = getService();
+  if (!service)
+    return;
+
+  service->SetMetadata(MediaMetadataSanitizer::sanitizeAndConvertToMojo(
+      m_metadata, getExecutionContext()));
+}
+
 const WTF::AtomicString& MediaSession::interfaceName() const {
   return EventTargetNames::MediaSession;
 }
 
 ExecutionContext* MediaSession::getExecutionContext() const {
   return ContextLifecycleObserver::getExecutionContext();
 }
 
 mojom::blink::MediaSessionService* MediaSession::getService() {
   if (m_service)
@@ skipping 51 matching lines @@
   dispatchEvent(Event::create(mojomActionToEventName(action)));
 }
 
 DEFINE_TRACE(MediaSession) {
   visitor->trace(m_metadata);
   EventTargetWithInlineData::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
 }
 
 }  // namespace blink