Have HTMLMediaElement::play() return a Promise.

third_party/WebKit/Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 2530 matching lines @@
         exceptionState.throwDOMException(InvalidAccessError, "No context document is available.");
         return 0;
     }
 
     return document->loader()->timing().monotonicTimeToZeroBasedDocumentTime(platformTime);
 }
 
 void Internals::setMediaElementNetworkState(HTMLMediaElement* mediaElement, int state)
 {
     ASSERT(mediaElement);
-    ASSERT(state >= HTMLMediaElement::NetworkState::NETWORK_EMPTY);
-    ASSERT(state <= HTMLMediaElement::NetworkState::NETWORK_NO_SOURCE);
+    ASSERT(state >= WebMediaPlayer::NetworkState::NetworkStateEmpty);
+    ASSERT(state <= WebMediaPlayer::NetworkState::NetworkStateDecodeError);
     mediaElement->setNetworkState(static_cast<WebMediaPlayer::NetworkState>(state));
 }
 
 // TODO(liberato): remove once autoplay gesture override experiment concludes.
 void Internals::triggerAutoplayViewportCheck(HTMLMediaElement* element)
 {
     element->triggerAutoplayViewportCheckForTesting();
 }
 
 int Internals::getScrollAnimationState(Node* node) const
 {
     if (ScrollableArea* scrollableArea = scrollableAreaForNode(node))
         return static_cast<int>(scrollableArea->scrollAnimator().m_runState);
     return -1;
 }
 
 } // namespace blink