Switch to using an explicit ended signal instead of time comparison.

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

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 2961 matching lines @@
     // spec says:
     // 4.8.8 - Dynamically modifying a source element and its attribute when the
     // element is already inserted in a video or audio element will have no
     // effect.
     m_currentSourceNode = nullptr;
     BLINK_MEDIA_LOG << "sourceWasRemoved(" << (void*)this
                     << ") - m_currentSourceNode set to 0";
   }
 }
 
-void HTMLMediaElement::timeChanged() {
+void HTMLMediaElement::timeChanged(bool ended) {
   BLINK_MEDIA_LOG << "timeChanged(" << (void*)this << ")";
 
   cueTimeline().updateActiveCues(currentTime());
 
   invalidateCachedTime();
 
   // 4.8.10.9 steps 12-14. Needed if no ReadyState change is associated with the
   // seek.
   if (m_seeking && m_readyState >= kHaveCurrentData &&
       !webMediaPlayer()->seeking())
     finishSeek();
 
   // Always call scheduleTimeupdateEvent when the media engine reports a time
   // discontinuity, it will only queue a 'timeupdate' event if we haven't
   // already posted one at the current movie time.
   scheduleTimeupdateEvent(false);
 
-  double now = currentTime();
-  double dur = duration();
-
-  // When the current playback position reaches the end of the media resource
-  // when the direction of playback is forwards, then the user agent must follow
-  // these steps:
-  if (!std::isnan(dur) && dur && now >= dur &&
-      getDirectionOfPlayback() == Forward) {
+  if (ended) {
     // If the media element has a loop attribute specified
     if (loop()) {
       //  then seek to the earliest possible position of the media resource and
       //  abort these steps.
       seek(0);
     } else {
       // If the media element has still ended playback, and the direction of
       // playback is still forwards, and paused is false,
       if (!m_paused) {
         // changes paused to true and fires a simple event named pause at the
@@ skipping 1074 matching lines @@
 
 IntRect HTMLMediaElement::AutoplayHelperClientImpl::absoluteBoundingBoxRect()
     const {
   IntRect result;
   if (LayoutObject* object = m_element->layoutObject())
     result = object->absoluteBoundingBoxRect();
   return result;
 }
 
 }  // namespace blink