Allow metadata preload on cellular connections and disallow autoplay muted for low end devices.

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 2047 matching lines @@
 String HTMLMediaElement::preload() const {
   return preloadTypeToString(preloadType());
 }
 
 void HTMLMediaElement::setPreload(const AtomicString& preload) {
   BLINK_MEDIA_LOG << "setPreload(" << (void*)this << ", " << preload << ")";
   setAttribute(preloadAttr, preload);
 }
 
 WebMediaPlayer::Preload HTMLMediaElement::preloadType() const {
-  // Force preload to none for cellular connections or when data saver is
-  // explicitly set.
-  if (networkStateNotifier().isCellularConnectionType() ||
-      (document().settings() &&
-       (document().settings()->dataSaverEnabled() ||
-        document().settings()->forcePreloadNoneForMediaElements()))) {
+  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.
+  if (document().settings() &&
+      (document().settings()->dataSaverEnabled() ||
+       document().settings()->forcePreloadNoneForMediaElements())) {
     UseCounter::count(document(),
                       UseCounter::HTMLMediaElementPreloadForcedNone);
     return WebMediaPlayer::PreloadNone;
   }
 
-  const AtomicString& preload = fastGetAttribute(preloadAttr);
-  if (equalIgnoringCase(preload, "none")) {
-    UseCounter::count(document(), UseCounter::HTMLMediaElementPreloadNone);
-    return WebMediaPlayer::PreloadNone;
-  }
   if (equalIgnoringCase(preload, "metadata")) {
     UseCounter::count(document(), UseCounter::HTMLMediaElementPreloadMetadata);
     return WebMediaPlayer::PreloadMetaData;
   }
+
+  // Force preload to 'metadata' on cellular connections.
+  if (networkStateNotifier().isCellularConnectionType()) {
+    UseCounter::count(document(),
+                      UseCounter::HTMLMediaElementPreloadForcedMetadata);
+    return WebMediaPlayer::PreloadMetaData;
+  }
+
   if (equalIgnoringCase(preload, "auto")) {
     UseCounter::count(document(), UseCounter::HTMLMediaElementPreloadAuto);
     return WebMediaPlayer::PreloadAuto;
   }
 
   // "The attribute's missing value default is user-agent defined, though the
   // Metadata state is suggested as a compromise between reducing server load
   // and providing an optimal user experience."
 
   // The spec does not define an invalid value default:
@@ skipping 1701 matching lines @@
 bool HTMLMediaElement::isGestureNeededForPlayback() const {
   if (!m_lockedPendingUserGesture)
     return false;
 
   if (loadType() == WebMediaPlayer::LoadTypeMediaStream)
     return false;
 
   // We want to allow muted video to autoplay if:
   // - the flag is enabled;
   // - Data Saver is not enabled;
+  // - Preload was not disabled (low end devices);
   // - Autoplay is enabled in settings;
   if (isHTMLVideoElement() && muted() &&
       RuntimeEnabledFeatures::autoplayMutedVideosEnabled() &&
       !(document().settings() && document().settings()->dataSaverEnabled()) &&
+      !(document().settings() &&
+        document().settings()->forcePreloadNoneForMediaElements()) &&
       isAutoplayAllowedPerSettings()) {
     return false;
   }
 
   if (m_autoplayHelper->isGestureRequirementOverridden())
     return false;
 
   return true;
 }
 
@@ skipping 269 matching lines @@
 
 IntRect HTMLMediaElement::AutoplayHelperClientImpl::absoluteBoundingBoxRect()
     const {
   IntRect result;
   if (LayoutObject* object = m_element->layoutObject())
     result = object->absoluteBoundingBoxRect();
   return result;
 }
 
 }  // namespace blink