Support 'extend-to-zoom' viewport descriptor value

Source/core/css/StyleRule.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 2008, 2012 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 408 matching lines @@
 
 void StyleRuleRegion::reportDescendantMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::CSS);
     info.addMember(m_selectorList, "selectorList");
 }
 
 StyleRuleViewport::StyleRuleViewport()
     : StyleRuleBase(Viewport, 0)
 {
-    ASSERT(RuntimeEnabledFeatures::cssViewportEnabled());
 }
 
 StyleRuleViewport::StyleRuleViewport(const StyleRuleViewport& o)
     : StyleRuleBase(o)
     , m_properties(o.m_properties->mutableCopy())
 {
-    ASSERT(RuntimeEnabledFeatures::cssViewportEnabled());
 }
 
 StyleRuleViewport::~StyleRuleViewport()
 {
 }
 
 MutableStylePropertySet* StyleRuleViewport::mutableProperties()
 {
     if (!m_properties->isMutable())
         m_properties = m_properties->mutableCopy();
@@ skipping 41 matching lines @@
 }
 
 void StyleRuleFilter::reportDescendantMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::CSS);
     info.addMember(m_filterName);
     info.addMember(m_properties);
 }
 
 } // namespace WebCore