Sending an async GET request for doc.written blocked scripts.

third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 129 matching lines @@
     if (visibility == ResourcePriority::Visible)
         priority = ResourceLoadPriorityHigh;
 
     // Resources before the first image are considered "early" in the document
     // and resources after the first image are "late" in the document.  Important to
     // note that this is based on when the preload scanner discovers a resource
     // for the most part so the main parser may not have reached the image element yet.
     if (type == Resource::Image)
         m_imageFetched = true;
 
-    // Special handling for scripts.
-    // Default/Parser-Blocking/Preload early in document: High (set in typeToPriority)
-    // Async/Defer: Low Priority (applies to both preload and parser-inserted)
-    // Preload late in document: Medium
-    if (type == Resource::Script) {
+    if (FetchRequest::IdleLoad == request.defer()) {
+        priority = ResourceLoadPriorityVeryLow;
+    } else if (type == Resource::Script) {
+        // Special handling for scripts.
+        // Default/Parser-Blocking/Preload early in document: High (set in typeToPriority)
+        // Async/Defer: Low Priority (applies to both preload and parser-inserted)
+        // Preload late in document: Medium
         if (FetchRequest::LazyLoad == request.defer())
             priority = ResourceLoadPriorityLow;
         else if (request.forPreload() && m_imageFetched)
             priority = ResourceLoadPriorityMedium;
     } else if (FetchRequest::LazyLoad == request.defer()) {
         priority = ResourceLoadPriorityVeryLow;
     }
 
     // A manually set priority acts as a floor. This is used to ensure that synchronous requests
     // are always given the highest possible priority, as well as to ensure that there isn't priority
@@ skipping 1149 matching lines @@
     visitor->trace(m_context);
     visitor->trace(m_archive);
     visitor->trace(m_loaders);
     visitor->trace(m_nonBlockingLoaders);
     visitor->trace(m_documentResources);
     visitor->trace(m_preloads);
     visitor->trace(m_resourceTimingInfoMap);
 }
 
 } // namespace blink