Support 'extend-to-zoom' viewport descriptor value

Source/core/css/CSSParser-in.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 11417 matching lines @@
     ASSERT(RuntimeEnabledFeatures::cssViewportEnabled());
 
     CSSParserValue* value = m_valueList->current();
     if (!value)
         return false;
 
     CSSValueID id = value->id;
     bool validPrimitive = false;
 
     switch (propId) {
-    case CSSPropertyMinWidth: // auto | <length> | <percentage>
+    case CSSPropertyMinWidth: // auto | extend-to-zoom | <length> | <percentage>
     case CSSPropertyMaxWidth:
     case CSSPropertyMinHeight:
     case CSSPropertyMaxHeight:
-        if (id == CSSValueAuto)
+        if (id == CSSValueAuto || id == CSSValueInternalExtendToZoom)
             validPrimitive = true;
         else
             validPrimitive = (!id && validUnit(value, FLength | FPercent | FNonNeg));
         break;
     case CSSPropertyWidth: // shorthand
         return parseViewportShorthand(propId, CSSPropertyMinWidth, CSSPropertyMaxWidth, important);
     case CSSPropertyHeight:
         return parseViewportShorthand(propId, CSSPropertyMinHeight, CSSPropertyMaxHeight, important);
     case CSSPropertyMinZoom: // auto | <number> | <percentage>
     case CSSPropertyMaxZoom:
@@ skipping 290 matching lines @@
 {
     // The tokenizer checks for the construct of an+b.
     // However, since the {ident} rule precedes the {nth} rule, some of those
     // tokens are identified as string literal. Furthermore we need to accept
     // "odd" and "even" which does not match to an+b.
     return equalIgnoringCase(token, "odd") || equalIgnoringCase(token, "even")
         || equalIgnoringCase(token, "n") || equalIgnoringCase(token, "-n");
 }
 
 }