Avoid double download for late discovered link preload resources.

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 4730 matching lines @@
         InspectorInstrumentation::domContentLoadedEventFired(frame.get());
     }
 
     // Schedule dropping of the ElementDataCache. We keep it alive for a while after parsing finishes
     // so that dynamically inserted content can also benefit from sharing optimizations.
     // Note that we don't refresh the timer on cache access since that could lead to huge caches being kept
     // alive indefinitely by something innocuous like JS setting .innerHTML repeatedly on a timer.
     m_elementDataCacheClearTimer.startOneShot(10, BLINK_FROM_HERE);
 
     // Parser should have picked up all preloads by now
-    m_fetcher->clearPreloads();
+    m_fetcher->clearPreloads(ResourceFetcher::ClearSpeculativeMarkupPreloads);
 }
 
 void Document::elementDataCacheClearTimerFired(Timer<Document>*)
 {
     m_elementDataCache.clear();
 }
 
 Vector<IconURL> Document::iconURLs(int iconTypesMask)
 {
     IconURL firstFavicon;
@@ skipping 1154 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif