Record autoplay disabled by sandbox flags.

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 243 matching lines @@
     // Media element with autoplay seen.
     AutoplayMediaFound = 0,
     // Autoplay enabled and user stopped media play at any point.
     AutoplayStopped = 1,
     // Autoplay enabled but user bailed out on media play early.
     AutoplayBailout = 2,
     // Autoplay disabled but user manually started media.
     AutoplayManualStart = 3,
     // Autoplay was (re)enabled through a user-gesture triggered load()
     AutoplayEnabledThroughLoad = 4,
+    // Autoplay disabled by sandbox flags.
+    AutoplayDisableddBySandbox = 5,

[fs, 2015/06/18 08:18:39]

Drive-by nit: Disabledd

     // This enum value must be last.
     NumberOfAutoplayMetrics,
 };
 
 static void recordAutoplayMetric(AutoplayMetrics metric)
 {
     Platform::current()->histogramEnumeration("Blink.MediaElement.Autoplay", metric, NumberOfAutoplayMetrics);
 }
 
 WebMimeRegistry::SupportsType HTMLMediaElement::supportsType(const ContentType& contentType, const String& keySystem)
@@ skipping 1255 matching lines @@
         shouldUpdateDisplayState = true;
     }
 
     if (m_readyState == HAVE_ENOUGH_DATA && oldState < HAVE_ENOUGH_DATA && tracksAreReady) {
         if (oldState <= HAVE_CURRENT_DATA) {
             scheduleEvent(EventTypeNames::canplay);
             if (isPotentiallyPlaying)
                 scheduleEvent(EventTypeNames::playing);
         }
 
-        if (m_autoplaying && m_paused && autoplay() && !document().isSandboxed(SandboxAutomaticFeatures)) {
+        if (m_autoplaying && m_paused && autoplay()) {
             autoplayMediaEncountered();
-            if (!m_userGestureRequiredForPlay) {
+
+            if (document().isSandboxed(SandboxAutomaticFeatures)) {
+                recordAutoplayMetric(AutoplayDisableddBySandbox);
+            } else if (!m_userGestureRequiredForPlay) {
                 m_paused = false;
                 invalidateCachedTime();
                 scheduleEvent(EventTypeNames::play);
                 scheduleEvent(EventTypeNames::playing);
             }
         }
 
         scheduleEvent(EventTypeNames::canplaythrough);
 
         shouldUpdateDisplayState = true;
@@ skipping 2115 matching lines @@
 
 #if ENABLE(WEB_AUDIO)
 void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
 {
     if (!Heap::isHeapObjectAlive(m_audioSourceNode) && audioSourceProvider())
         audioSourceProvider()->setClient(nullptr);
 }
 #endif
 
 }