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 0afbb0d8c1483b93121fc7f133fb10a5b3177c1b..40b4cf91ec85a78fe472cd91c28c4203ebed8dc5 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"
@@ -16,8 +17,65 @@
 
 namespace blink {
 
+namespace {
+
+Vector<AtomicString>* createActionEnumToEventNameVec() {
+  Vector<AtomicString>* vec = new Vector<AtomicString>();

[haraken, 2016/10/17 22:37:05]

Use std::unique_ptr.

However, why do you need to create the vector dynamically? It would be nicer to
use a switch statement or a static array.

[Zhiqiang Zhang (Slow), 2016/10/18 14:42:14]

It is actually used in DEFINE_THREAD_SAFE_STATIC_LOCAL (see below).
I've merged this function as a lambda into getActionEnumToEventNameVec().

+  // Must be in the same order. There's a possible HashMap bug that prevents
+  // mapping 0 to String. See https://crbug.com/656795
+  vec->append(EventTypeNames::play);
+  vec->append(EventTypeNames::pause);
+  vec->append(EventTypeNames::playpause);
+  vec->append(EventTypeNames::previoustrack);
+  vec->append(EventTypeNames::nexttrack);
+  vec->append(EventTypeNames::seekforward);
+  vec->append(EventTypeNames::seekbackward);
+
+  return vec;
+}
+
+// Map from MediaSessionAction to EventTypeName.
+const Vector<AtomicString>& getActionEnumToEventNameVec() {
+  DEFINE_THREAD_SAFE_STATIC_LOCAL(Vector<AtomicString>,
+                                  actionEnumToEventNameVec,
+                                  createActionEnumToEventNameVec());
+  return actionEnumToEventNameVec;
+}
+
+using StringToActionEnumMap =
+    HashMap<AtomicString, blink::mojom::blink::MediaSessionAction>;
+
+StringToActionEnumMap* createEventNameToActionEnumMap() {
+  StringToActionEnumMap* map = new StringToActionEnumMap();

[haraken, 2016/10/17 22:37:05]

Ditto.

[Zhiqiang Zhang (Slow), 2016/10/18 14:42:14]

Ditto as the other reply.

+  map->add(EventTypeNames::play, blink::mojom::blink::MediaSessionAction::PLAY);
+  map->add(EventTypeNames::pause,
+           blink::mojom::blink::MediaSessionAction::PAUSE);
+  map->add(EventTypeNames::playpause,
+           blink::mojom::blink::MediaSessionAction::PLAY_PAUSE);
+  map->add(EventTypeNames::previoustrack,
+           blink::mojom::blink::MediaSessionAction::PREVIOUS_TRACK);
+  map->add(EventTypeNames::nexttrack,
+           blink::mojom::blink::MediaSessionAction::NEXT_TRACK);
+  map->add(EventTypeNames::seekforward,
+           blink::mojom::blink::MediaSessionAction::SEEK_FORWARD);
+  map->add(EventTypeNames::seekbackward,
+           blink::mojom::blink::MediaSessionAction::SEEK_BACKWARD);
+
+  return map;
+}
+
+// Map from EventTypeName to MediaSessionAction.
+const StringToActionEnumMap& getEventNameToActionEnumMap() {
+  DEFINE_THREAD_SAFE_STATIC_LOCAL(StringToActionEnumMap,
+                                  eventNameToActionEnumMap,
+                                  createEventNameToActionEnumMap());
+  return eventNameToActionEnumMap;
+}
+
+}  // anonymous namespace
+
 MediaSession::MediaSession(ScriptState* scriptState)
-    : m_scriptState(scriptState) {}
+    : m_scriptState(scriptState), m_clientBinding(this) {}
 
 MediaSession* MediaSession::create(ScriptState* scriptState) {
   return new MediaSession(scriptState);
@@ -55,6 +113,8 @@ mojom::blink::MediaSessionService* MediaSession::getService(
 
     if (interfaceProvider)
       interfaceProvider->getInterface(mojo::GetProxy(&m_service));
+
+    m_service->SetClient(m_clientBinding.CreateInterfacePtrAndBind());
   }
   return m_service.get();
 }
@@ -63,18 +123,46 @@ bool MediaSession::addEventListenerInternal(
     const AtomicString& eventType,
     EventListener* listener,
     const AddEventListenerOptionsResolved& options) {
-  // TODO(zqzhang): Notify MediaSessionService the handler has been set. See
-  // https://crbug.com/656563
-  return EventTarget::addEventListenerInternal(eventType, listener, options);
+  bool result =
+      EventTarget::addEventListenerInternal(eventType, listener, options);
+
+  const auto& map = getEventNameToActionEnumMap();
+  auto iter = map.find(eventType);
+  if (iter != map.end()) {
+    if (mojom::blink::MediaSessionService* service =
+            getService(m_scriptState.get())) {
+      service->EnableAction(iter->value);
+    }
+  }
+  return result;
 }
 
 bool MediaSession::removeEventListenerInternal(
     const AtomicString& eventType,
     const EventListener* listener,
     const EventListenerOptions& options) {
-  // TODO(zqzhang): Notify MediaSessionService the handler has been unset. See
-  // https://crbug.com/656563
-  return EventTarget::removeEventListenerInternal(eventType, listener, options);
+  bool result =
+      EventTarget::removeEventListenerInternal(eventType, listener, options);
+
+  const auto& map = getEventNameToActionEnumMap();
+  auto iter = map.find(eventType);
+  if (iter != map.end()) {
+    if (mojom::blink::MediaSessionService* service =
+            getService(m_scriptState.get())) {
+      service->DisableAction(iter->value);
+    }
+  }
+  return result;
+}
+
+void MediaSession::DidReceivedAction(
+    blink::mojom::blink::MediaSessionAction action) {
+  LOG(INFO) << static_cast<int>(action);
+  const auto& vec = getActionEnumToEventNameVec();
+  if (static_cast<int>(action) >= 0 &&
+      static_cast<size_t>(action) < vec.size()) {
+    dispatchEvent(Event::create(vec[static_cast<int>(action)]));
+  }
 }
 
 DEFINE_TRACE(MediaSession) {