Support 'extend-to-zoom' viewport descriptor value

Source/core/dom/ViewportArguments.h

 /*
  * 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 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
- * Copyright (C) 2012 Intel Corporation. All rights reserved.
+ * Copyright (C) 2012-2013 Intel Corporation. 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
@@ skipping 38 matching lines @@
 
     enum {
         ValueAuto = -1,
         ValueDeviceWidth = -2,
         ValueDeviceHeight = -3,
         ValuePortrait = -4,
         ValueLandscape = -5,
         ValueDeviceDPI = -6,
         ValueLowDPI = -7,
         ValueMediumDPI = -8,
-        ValueHighDPI = -9
+        ValueHighDPI = -9,
+        ValueExtendToZoom = -10
     };
 
     ViewportArguments(Type type = Implicit)
         : type(type)
         , width(ValueAuto)
         , minWidth(ValueAuto)
         , maxWidth(ValueAuto)
         , height(ValueAuto)
         , minHeight(ValueAuto)
         , maxHeight(ValueAuto)
@@ skipping 45 matching lines @@
         return !(*this == other);
     }
 };
 
 void setViewportFeature(const String& keyString, const String& valueString, Document*, void* data);
 void reportViewportWarning(Document*, ViewportErrorCode, const String& replacement1, const String& replacement2);
 
 } // namespace WebCore
 
 #endif // ViewportArguments_h