Prerender: Disable prefetch if there's an appcache.

third_party/WebKit/Source/core/html/parser/HTMLDocumentParser.cpp

 /*
  * Copyright (C) 2010 Google, 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 877 matching lines @@
 
   // We should never reach this point if we're using a parser thread, as
   // appendBytes() will directly ship the data to the thread.
   DCHECK(!ShouldUseThreading());
 
   TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("blink.debug"),
                "HTMLDocumentParser::append", "size", input_source.length());
   const SegmentedString source(input_source);
 
   if (GetDocument()->IsPrefetchOnly()) {
+    // Do not prefetch if there is an appcache.
+    if (GetDocument()->Loader()->GetResponse().AppCacheID() != 0)
+      return;
+
     if (!preload_scanner_)
       preload_scanner_ = CreatePreloadScanner();
 
     preload_scanner_->AppendToEnd(source);
     ScanAndPreload(preload_scanner_.get());
 
     // Return after the preload scanner, do not actually parse the document.
     return;
   }
 
@@ skipping 421 matching lines @@
     success_histogram.Count(duration);
   } else {
     DEFINE_STATIC_LOCAL(
         CustomCountHistogram, failure_histogram,
         ("PreloadScanner.DocumentWrite.ExecutionTime.Failure", 1, 10000, 50));
     failure_histogram.Count(duration);
   }
 }
 
 }  // namespace blink