Demote 'line-height' to a low priority property.

Source/core/css/resolver/StyleResolverState.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 19 matching lines @@
 namespace blink {
 
 StyleResolverState::StyleResolverState(Document& document, Element* element, RenderStyle* parentStyle)
     : m_elementContext(element ? ElementResolveContext(*element) : ElementResolveContext(document))
     , m_document(document)
     , m_style(nullptr)
     , m_cssToLengthConversionData(0, rootElementStyle(), document.renderView())
     , m_parentStyle(parentStyle)
     , m_applyPropertyToRegularStyle(true)
     , m_applyPropertyToVisitedLinkStyle(false)
-    , m_lineHeightValue(nullptr)
     , m_fontBuilder(document)
     , m_styleMap(*this, m_elementStyleResources)
 {
     if (!parentStyle && m_elementContext.parentNode())
         m_parentStyle = m_elementContext.parentNode()->renderStyle();
 
     ASSERT(document.isActive());
     m_elementStyleResources.setDeviceScaleFactor(document.frameHost()->deviceScaleFactor());
 }
 
 StyleResolverState::~StyleResolverState()
 {
 }
 
 void StyleResolverState::setAnimationUpdate(PassOwnPtrWillBeRawPtr<CSSAnimationUpdate> update)
 {
     m_animationUpdate = update;
 }
 
 PassOwnPtrWillBeRawPtr<CSSAnimationUpdate> StyleResolverState::takeAnimationUpdate()
 {
     return m_animationUpdate.release();
 }
 
 } // namespace blink