Measure the impact of a proposed media element load algorithm change

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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 777 matching lines @@
         // FIXME: Add support for firing this event.
 
         // 4.8 - Set the initial playback position to 0.
         // FIXME: Make this less subtle. The position only becomes 0 because the ready state is HAVE_NOTHING.
         invalidateCachedTime();
 
         // 4.9 - Set the timeline offset to Not-a-Number (NaN).
         // 4.10 - Update the duration attribute to Not-a-Number (NaN).
 
         cueTimeline().updateActiveCues(0);
+    } else if (!m_paused) {
+        // TODO(philipj): There is a proposal to always reset the paused state
+        // in the media element load algorithm, to avoid a bogus play() promise
+        // rejection: https://github.com/whatwg/html/issues/869
+        // This is where that change would have an effect, and it is measured to
+        // verify the assumption that it's a very rare situation.
+        UseCounter::count(document(), UseCounter::HTMLMediaElementLoadNetworkEmptyNotPaused);
     }
 
     // 5 - Set the playbackRate attribute to the value of the defaultPlaybackRate attribute.
     setPlaybackRate(defaultPlaybackRate());
 
     // 6 - Set the error attribute to null and the autoplaying flag to true.
     m_error = nullptr;
     m_autoplaying = true;
 
     // 7 - Invoke the media element's resource selection algorithm.
@@ skipping 2996 matching lines @@
 {
     visitor->trace(m_client);
 }
 
 DEFINE_TRACE(HTMLMediaElement::AudioSourceProviderImpl)
 {
     visitor->trace(m_client);
 }
 
 } // namespace blink