Adding mojo MediaSessionClient to support media controls

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

Index: third_party/WebKit/Source/modules/mediasession/MediaSession.cpp
diff --git a/third_party/WebKit/Source/modules/mediasession/MediaSession.cpp b/third_party/WebKit/Source/modules/mediasession/MediaSession.cpp
index 2c909379aa49f3c1ed6526496fea06ee59cebce0..6c91cf55f22318676b917bdc4e348936726df6a4 100644
--- a/third_party/WebKit/Source/modules/mediasession/MediaSession.cpp
+++ b/third_party/WebKit/Source/modules/mediasession/MediaSession.cpp
@@ -7,6 +7,7 @@
 #include "bindings/core/v8/ScriptState.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
+#include "core/events/Event.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/EventTargetModules.h"
 #include "modules/mediasession/MediaMetadata.h"
@@ -17,7 +18,7 @@
 namespace blink {
 
 MediaSession::MediaSession(ScriptState* scriptState)
-    : m_scriptState(scriptState) {}
+    : m_scriptState(scriptState), m_clientBinding(this) {}
 
 MediaSession* MediaSession::create(ScriptState* scriptState) {
   return new MediaSession(scriptState);
@@ -55,18 +56,23 @@ mojom::blink::MediaSessionService* MediaSession::getService(
 
     if (interfaceProvider)
       interfaceProvider->getInterface(mojo::GetProxy(&m_service));
+
+    m_service->SetClient(m_clientBinding.CreateInterfacePtrAndBind());
   }
   return m_service.get();
 }
 
-// TODO(zqzhang): register listener to MediaSessionService. See
-// https://crbug.com/xxxxxx
-#define DEFINE_MEDIA_SESSION_ATTRIBUTE_EVENT_LISTENER(attribute)    \
-  EventListener* MediaSession::on##attribute() {                    \
-    return getAttributeEventListener(EventTypeNames::attribute);    \
-  }                                                                 \
-  void MediaSession::setOn##attribute(EventListener* listener) {    \
-    setAttributeEventListener(EventTypeNames::attribute, listener); \
+#define DEFINE_MEDIA_SESSION_ATTRIBUTE_EVENT_LISTENER(attribute)         \
+  EventListener* MediaSession::on##attribute() {                         \
+    return getAttributeEventListener(EventTypeNames::attribute);         \
+  }                                                                      \
+  void MediaSession::setOn##attribute(EventListener* listener) {         \
+    setAttributeEventListener(EventTypeNames::attribute, listener);      \
+    if (mojom::blink::MediaSessionService* service =                     \
+            getService(m_scriptState.get())) {                           \
+      service->DidSetEventHandlerForAction(EventTypeNames::attribute,    \
+                                           static_cast<bool>(listener)); \
+    }                                                                    \
   }
 
 DEFINE_MEDIA_SESSION_ATTRIBUTE_EVENT_LISTENER(play);
@@ -77,6 +83,11 @@ DEFINE_MEDIA_SESSION_ATTRIBUTE_EVENT_LISTENER(nexttrack);
 DEFINE_MEDIA_SESSION_ATTRIBUTE_EVENT_LISTENER(seekforward);
 DEFINE_MEDIA_SESSION_ATTRIBUTE_EVENT_LISTENER(seekbackward);
 
+void MediaSession::DidReceivedAction(const WTF::String& action) {
+  StringView view(action);
+  dispatchEvent(Event::create(view.toAtomicString()));
+}
+
 DEFINE_TRACE(MediaSession) {
   visitor->trace(m_metadata);
   EventTargetWithInlineData::trace(visitor);