Replace raw pointers to GC allocated objects by members in stack allocated objects.

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 WebCore {
 
 StyleResolverState::StyleResolverState(Document& document, Element* element, RenderStyle* parentStyle)
     : m_elementContext(element ? ElementResolveContext(*element) : ElementResolveContext())
     , m_document(document)
     , m_style(nullptr)
     , m_cssToLengthConversionData(0, rootElementStyle(), document.renderView())
     , m_parentStyle(parentStyle)
     , m_applyPropertyToRegularStyle(true)
     , m_applyPropertyToVisitedLinkStyle(false)
-    , m_lineHeightValue(0)
+    , m_lineHeightValue(nullptr)
     , m_styleMap(*this, m_elementStyleResources)
-    , m_currentRule(0)
+    , m_currentRule(nullptr)

[haraken, 2014/03/24 07:05:03]

Can we detect an error if we forget to initialize a Member in a stack-allocated
object with nullptr ?

[Mads Ager (chromium), 2014/03/24 07:24:43]

Drive-by answer: Member initializes itself with zero in any case, so we do not
have to initialize them with nullptr. The thing that becomes dangerous is
RawPtr. In the end those will become raw pointers that we have to properly
initialize.

Come to think of it, maybe we should initialize RawPtr with a recognizable zap
value instead of 0. They represent raw pointers and therefore they should always
be explicitly initialized to zero if that is what we want. Otherwise, we are in
for surprises when we move from: RawPtr<A> a; to A* a;

[haraken, 2014/03/24 07:36:21]

This sounds like a good idea.

 {
     if (!parentStyle && m_elementContext.parentNode())
         m_parentStyle = m_elementContext.parentNode()->renderStyle();
 
     // FIXME: Animation unitests will start animations on non-active documents!
     // http://crbug.com/330095
     // ASSERT(document.isActive());
     if (!document.isActive())
         return;
     m_elementStyleResources.setDeviceScaleFactor(document.frameHost()->deviceScaleFactor());
 }
 
 StyleResolverState::~StyleResolverState()
 {
 }
 
 void StyleResolverState::setAnimationUpdate(PassOwnPtr<CSSAnimationUpdate> update)
 {
     m_animationUpdate = update;
 }
 
 PassOwnPtr<CSSAnimationUpdate> StyleResolverState::takeAnimationUpdate()
 {
     return m_animationUpdate.release();
 }
 
 } // namespace WebCore