Have HTMLMediaElement::play() return a Promise.

third_party/WebKit/Source/core/html/HTMLMediaElement.h

Index: third_party/WebKit/Source/core/html/HTMLMediaElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLMediaElement.h b/third_party/WebKit/Source/core/html/HTMLMediaElement.h
index 6d9157f8db8f8c50a7e3d6a60212167a8dedaf9e..15a28683135e6e6b1c265335c41751e1d746cb15 100644
--- a/third_party/WebKit/Source/core/html/HTMLMediaElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLMediaElement.h
@@ -26,8 +26,10 @@
 #ifndef HTMLMediaElement_h
 #define HTMLMediaElement_h
 
+#include "bindings/core/v8/ScriptPromise.h"
 #include "core/CoreExport.h"
 #include "core/dom/ActiveDOMObject.h"
+#include "core/dom/ExceptionCode.h"
 #include "core/events/GenericEventQueue.h"
 #include "core/html/AutoplayExperimentHelper.h"
 #include "core/html/HTMLElement.h"
@@ -52,6 +54,7 @@ class KURL;
 class MediaControls;
 class MediaError;
 class HTMLMediaSource;
+class ScriptState;
 class TextTrackContainer;
 class TextTrackList;
 class TimeRanges;
@@ -136,7 +139,8 @@ public:
     bool shouldAutoplay(const RecordMetricsBehavior = RecordMetricsBehavior::DoNotRecord);
     bool loop() const;
     void setLoop(bool);
-    void play();
+    ScriptPromise playForBindings(ScriptState*);
+    Nullable<ExceptionCode> play();
     void pause();
     void requestRemotePlayback();
     void requestRemotePlaybackControl();
@@ -445,6 +449,13 @@ private:
     // TODO(liberato): remove once autoplay gesture override experiment concludes.
     void triggerAutoplayViewportCheckForTesting();
 
+    void scheduleResolvePlayPromises();
+    void scheduleRejectPlayPromises(ExceptionCode, const String&);
+    void scheduleNotifyPlaying();
+
+    void resolvePlayPromises();
+    void rejectPlayPromises(ExceptionCode, const String&);
+
     UnthrottledTimer<HTMLMediaElement> m_loadTimer;
     UnthrottledTimer<HTMLMediaElement> m_progressEventTimer;
     UnthrottledTimer<HTMLMediaElement> m_playbackProgressTimer;
@@ -553,6 +564,8 @@ private:
 
     OwnPtrWillBeMember<CueTimeline> m_cueTimeline;
 
+    PersistentHeapVectorWillBeHeapVector<Member<ScriptPromiseResolver>> m_playResolvers;
+
     // This is a weak reference, since m_audioSourceNode holds a reference to us.
     // FIXME: Oilpan: Consider making this a strongly traced pointer with oilpan where strong cycles are not a problem.
     GC_PLUGIN_IGNORE("http://crbug.com/404577")