[Blink>MediaSession] Use setActionCallback() instead of event listeners for media control actions

third_party/WebKit/Source/modules/mediasession/MediaSession.h

 // 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 MediaSession_h
 #define MediaSession_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
+#include "bindings/core/v8/TraceWrapperMember.h"
 #include "core/dom/ContextLifecycleObserver.h"
-#include "core/events/EventTarget.h"
 #include "modules/ModulesExport.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "platform/heap/Handle.h"
 #include "public/platform/modules/mediasession/media_session.mojom-blink.h"
+#include "wtf/text/WTFString.h"
 #include <memory>
 
 namespace blink {
 
 class ExecutionContext;
 class MediaMetadata;
+class MediaSessionActionHandler;
 
 class MODULES_EXPORT MediaSession final
-    : public EventTargetWithInlineData,
+    : public GarbageCollectedFinalized<MediaSession>,
       public ContextClient,
+      public ScriptWrappable,
       blink::mojom::blink::MediaSessionClient {
   USING_GARBAGE_COLLECTED_MIXIN(MediaSession);
   DEFINE_WRAPPERTYPEINFO();
   USING_PRE_FINALIZER(MediaSession, dispose);
 
  public:
   static MediaSession* create(ExecutionContext*);
 
   void dispose();
 
   void setPlaybackState(const String&);
   String playbackState();
 
   void setMetadata(MediaMetadata*);
   MediaMetadata* metadata() const;
 
-  // EventTarget implementation.
-  const WTF::AtomicString& interfaceName() const override;
-  ExecutionContext* getExecutionContext() const override;
+  void setActionHandler(const String& action, MediaSessionActionHandler*);
 
   // Called by the MediaMetadata owned by |this| when it has updates. Also used
   // internally when a new MediaMetadata object is set.
   void onMetadataChanged();
 
-  DEFINE_ATTRIBUTE_EVENT_LISTENER(play);
-  DEFINE_ATTRIBUTE_EVENT_LISTENER(pause);
-  DEFINE_ATTRIBUTE_EVENT_LISTENER(previoustrack);
-  DEFINE_ATTRIBUTE_EVENT_LISTENER(nexttrack);
-  DEFINE_ATTRIBUTE_EVENT_LISTENER(seekforward);
-  DEFINE_ATTRIBUTE_EVENT_LISTENER(seekbackward);
-
   DECLARE_VIRTUAL_TRACE();
+  DECLARE_VIRTUAL_TRACE_WRAPPERS();
 
  private:
+  friend class V8MediaSession;
   friend class MediaSessionTest;
 
+  enum class ActionChangeType {
+    ActionEnabled,
+    ActionDisabled,
+  };
+
   explicit MediaSession(ExecutionContext*);
 
-  // EventTarget overrides
-  bool addEventListenerInternal(
-      const AtomicString& eventType,
-      EventListener*,
-      const AddEventListenerOptionsResolved&) override;
-  bool removeEventListenerInternal(const AtomicString& eventType,
-                                   const EventListener*,
-                                   const EventListenerOptions&) override;
+  void notifyActionChange(const String& action, ActionChangeType);
 
   // blink::mojom::blink::MediaSessionClient implementation.
   void DidReceiveAction(blink::mojom::blink::MediaSessionAction) override;
 
+  void setV8ReferencesForHandlers(v8::Isolate*,
+                                  const v8::Persistent<v8::Object>& wrapper);
+
   // Returns null when the ExecutionContext is not document.
   mojom::blink::MediaSessionService* getService();
 
   mojom::blink::MediaSessionPlaybackState m_playbackState;
   Member<MediaMetadata> m_metadata;
+  HeapHashMap<String, TraceWrapperMember<MediaSessionActionHandler>>
+      m_actionHandlers;
   mojom::blink::MediaSessionServicePtr m_service;
   mojo::Binding<blink::mojom::blink::MediaSessionClient> m_clientBinding;
 };
 
 }  // namespace blink
 
 #endif  // MediaSession_h