Improve RAII of StyleResolverState.

Source/core/css/resolver/ElementResolveContext.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,
  * 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.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #include "config.h"
 #include "core/css/resolver/ElementResolveContext.h"
 
+#include "core/animation/ActiveAnimations.h"
 #include "core/dom/Node.h"
 #include "core/dom/NodeRenderStyle.h"
 #include "core/dom/NodeRenderingTraversal.h"
 #include "core/dom/VisitedLinkState.h"
+#include "core/rendering/style/RenderStyle.h"
 
 namespace blink {
 
-ElementResolveContext::ElementResolveContext(const Document& document)
-    : m_element(nullptr)
+static RenderStyle* findRootElementStyle(const Document& document, Element* element)
+{
+    Node* documentElement = document.documentElement();
+    if (documentElement && element != documentElement && documentElement->renderStyle())
+        return documentElement->renderStyle();
+    return document.renderStyle();
+}
+
+ElementResolveContext::ElementResolveContext(Document& document, Element* element, RenderStyle* parentStyle)
+    : m_document(document)
+    , m_element(element)
     , m_parentNode(nullptr)
-    , m_rootElementStyle(document.documentElement() ? document.documentElement()->renderStyle() : document.renderStyle())
-    , m_elementLinkState(NotInsideLink)
+    , m_parentStyle(parentStyle)
+    , m_activeAnimations(element ? element->activeAnimations() : nullptr)
+    , m_baseRenderStyle(m_activeAnimations ? m_activeAnimations->baseRenderStyle() : nullptr)
+    , m_rootElementStyle(findRootElementStyle(document, element))
+    , m_elementLinkState(element ? document.visitedLinkState().determineLinkState(*element) : NotInsideLink)
     , m_distributedToInsertionPoint(false)
 {
-}
+    if (element) {
+        NodeRenderingTraversal::ParentDetails parentDetails;
+        m_parentNode = NodeRenderingTraversal::parent(element, &parentDetails);
+        m_distributedToInsertionPoint = parentDetails.insertionPoint();
 
-ElementResolveContext::ElementResolveContext(Element& element)
-    : m_element(&element)
-    , m_elementLinkState(element.document().visitedLinkState().determineLinkState(element))
-    , m_distributedToInsertionPoint(false)
-{
-    NodeRenderingTraversal::ParentDetails parentDetails;
-    m_parentNode = NodeRenderingTraversal::parent(&element, &parentDetails);
-    m_distributedToInsertionPoint = parentDetails.insertionPoint();
-
-    const Document& document = element.document();
-    Node* documentElement = document.documentElement();
-    RenderStyle* documentStyle = document.renderStyle();
-    m_rootElementStyle = documentElement && element != documentElement ? documentElement->renderStyle() : documentStyle;
-    if (!m_rootElementStyle)
-        m_rootElementStyle = documentStyle;
+        if (!m_parentStyle && m_parentNode)
+            m_parentStyle = m_parentNode->renderStyle();
+    }
 }
 
 } // namespace blink