Fix a double download issue on desktop

Source/core/html/parser/HTMLPreloadScanner.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
  * 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.
@@ skipping 418 matching lines @@
     scanCommon(token, source, requests);
 }
 
 void TokenPreloadScanner::scan(const CompactHTMLToken& token, const SegmentedString& source, PreloadRequestStream& requests)
 {
     scanCommon(token, source, requests);
 }
 
 static void handleMetaViewport(const String& attributeValue, CachedDocumentParameters* documentParameters)
 {
+    if (!documentParameters->viewportMetaEnabled)
+        return;
     ViewportDescription description(ViewportDescription::ViewportMeta);
     HTMLMetaElement::getViewportDescriptionFromContentAttribute(attributeValue, description, nullptr, documentParameters->viewportMetaZeroValuesQuirk);
     FloatSize initialViewport(documentParameters->mediaValues->viewportHeight(), documentParameters->mediaValues->viewportWidth());
     PageScaleConstraints constraints = description.resolve(initialViewport, documentParameters->defaultViewportMinWidth);
     MediaValuesCached* cachedMediaValues = static_cast<MediaValuesCached*>(documentParameters->mediaValues.get());
     cachedMediaValues->setViewportHeight(constraints.layoutSize.height());
     cachedMediaValues->setViewportWidth(constraints.layoutSize.width());
 }
 
 template<typename Token>
@@ skipping 145 matching lines @@
 {
     ASSERT(isMainThread());
     ASSERT(document);
     if (givenMediaValues)
         mediaValues = givenMediaValues;
     else
         mediaValues = MediaValuesCached::create(*document);
     ASSERT(mediaValues->isSafeToSendToAnotherThread());
     defaultViewportMinWidth = document->viewportDefaultMinWidth();
     viewportMetaZeroValuesQuirk = document->settings() && document->settings()->viewportMetaZeroValuesQuirk();
+    viewportMetaEnabled = document->settings() && document->settings()->viewportMetaEnabled();
 }
 
 }