Add <meta viewport> support to the preloader

Source/core/html/HTMLMetaElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2010 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 24 matching lines @@
     TruncatedViewportArgumentValueError,
     MaximumScaleTooLargeError,
     TargetDensityDpiUnsupported
 };
 
 class CORE_EXPORT HTMLMetaElement final : public HTMLElement {
     DEFINE_WRAPPERTYPEINFO();
 public:
     DECLARE_NODE_FACTORY(HTMLMetaElement);
 
-    void getViewportDescriptionFromContentAttribute(const String& content, ViewportDescription::Type origin, ViewportDescription&, Document*, bool viewportMetaZeroValuesQuirk);
+    static void getViewportDescriptionFromContentAttribute(const String& content, ViewportDescription&, Document*, bool viewportMetaZeroValuesQuirk);
 
     const AtomicString& content() const;
     const AtomicString& httpEquiv() const;
     const AtomicString& name() const;
 
 private:
     explicit HTMLMetaElement(Document&);
 
     static void processViewportKeyValuePair(Document*, const String& key, const String& value, bool viewportMetaZeroValuesQuirk, void* data);
     static void parseContentAttribute(const String& content, void* data, Document*, bool viewportMetaZeroValuesQuirk);
@@ skipping 11 matching lines @@
 
     static void reportViewportWarning(Document*, ViewportErrorCode, const String& replacement1, const String& replacement2);
 
     void process();
     void processViewportContentAttribute(const String& content, ViewportDescription::Type origin);
 };
 
 } // namespace blink
 
 #endif // HTMLMetaElement_h