[MediaElement] Allow preloading for non-network scheme src

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 2052 matching lines @@
   setAttribute(preloadAttr, preload);
 }
 
 WebMediaPlayer::Preload HTMLMediaElement::preloadType() const {
   const AtomicString& preload = fastGetAttribute(preloadAttr);
   if (equalIgnoringCase(preload, "none")) {
     UseCounter::count(document(), UseCounter::HTMLMediaElementPreloadNone);
     return WebMediaPlayer::PreloadNone;
   }
 
   // Force preload to 'none' on Data Saver and for low end devices.

[mlamouri (slow - plz ping), 2016/12/05 13:32:44]

Can you update the comment? Or actually remove it because it just describes in
words what's in the condition.

[Zhiqiang Zhang (Slow), 2016/12/05 16:32:19]

Updated comments.

   if (document().settings() &&
       (document().settings()->dataSaverEnabled() ||
-       document().settings()->forcePreloadNoneForMediaElements())) {
+       document().settings()->forcePreloadNoneForMediaElements()) &&
+      (m_currentSrc.protocol() != "blob" && m_currentSrc.protocol() != "data" &&
+       m_currentSrc.protocol() != "file")) {
     UseCounter::count(document(),
                       UseCounter::HTMLMediaElementPreloadForcedNone);
     return WebMediaPlayer::PreloadNone;
   }
 
   if (equalIgnoringCase(preload, "metadata")) {
     UseCounter::count(document(), UseCounter::HTMLMediaElementPreloadMetadata);
     return WebMediaPlayer::PreloadMetaData;
   }
 
@@ skipping 1990 matching lines @@
       kMostlyFillViewportBecomeStableSeconds, BLINK_FROM_HERE);
 }
 
 void HTMLMediaElement::viewportFillDebouncerTimerFired(TimerBase*) {
   m_mostlyFillingViewport = true;
   if (m_webMediaPlayer)
     m_webMediaPlayer->becameDominantVisibleContent(m_mostlyFillingViewport);
 }
 
 }  // namespace blink