Make RenderObject::style() return a const object

Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 543 matching lines @@
     adjuster.adjustLayoutStyle(state.mutableStyleRef(), *state.parentStyle(), element, authorStyleInfo(state));
 }
 
 // Start loading resources referenced by this style.
 void StyleResolver::loadPendingResources(StyleResolverState& state)
 {
     m_styleResourceLoader.loadPendingResources(state.style(), state.elementStyleResources());
     document().styleEngine()->fontSelector()->fontLoader()->loadPendingFonts();
 }
 
-PassRefPtr<LayoutStyle> StyleResolver::styleForElement(Element* element, LayoutStyle* defaultParent, StyleSharingBehavior sharingBehavior,
+PassRefPtr<LayoutStyle> StyleResolver::styleForElement(Element* element, const LayoutStyle* defaultParent, StyleSharingBehavior sharingBehavior,
     RuleMatchingBehavior matchingBehavior)
 {
     ASSERT(document().frame());
     ASSERT(document().settings());
     ASSERT(!hasPendingAuthorStyleSheets());
     ASSERT(!m_needCollectFeatures);
 
     // Once an element has a renderer, we don't try to destroy it, since otherwise the renderer
     // will vanish if a style recalc happens during loading.
     if (sharingBehavior == AllowStyleSharing && !document().isRenderingReady() && !element->renderer()) {
@@ skipping 36 matching lines @@
         } else {
             state.setStyle(defaultStyleForElement());
             state.setParentStyle(LayoutStyle::clone(*state.style()));
         }
     }
 
     // contenteditable attribute (implemented by -webkit-user-modify) should
     // be propagated from shadow host to distributed node.
     if (state.distributedToInsertionPoint()) {
         if (Element* parent = element->parentElement()) {
-            if (LayoutStyle* styleOfShadowHost = parent->layoutStyle())
+            if (LayoutStyle* styleOfShadowHost = parent->mutableLayoutStyle())
                 state.style()->setUserModify(styleOfShadowHost->userModify());
         }
     }
 
     if (element->isLink()) {
         state.style()->setIsLink(true);
         EInsideLink linkState = state.elementLinkState();
         if (linkState != NotInsideLink) {
             bool forceVisited = InspectorInstrumentation::forcePseudoState(element, CSSSelector::PseudoVisited);
             if (forceVisited)
@@ skipping 43 matching lines @@
 
     setAnimationUpdateIfNeeded(state, *element);
 
     if (state.style()->hasViewportUnits())
         document().setHasViewportUnits();
 
     // Now return the style.
     return state.takeStyle();
 }
 
-PassRefPtr<LayoutStyle> StyleResolver::styleForKeyframe(Element& element, const LayoutStyle& elementStyle, LayoutStyle* parentStyle, const StyleRuleKeyframe* keyframe, const AtomicString& animationName)
+PassRefPtr<LayoutStyle> StyleResolver::styleForKeyframe(Element& element, const LayoutStyle& elementStyle, const LayoutStyle* parentStyle, const StyleRuleKeyframe* keyframe, const AtomicString& animationName)
 {
     ASSERT(document().frame());
     ASSERT(document().settings());
     ASSERT(!hasPendingAuthorStyleSheets());
 
     StyleResolverState state(document(), &element, parentStyle);
 
     MatchResult result;
     result.addMatchedProperties(&keyframe->properties());
 
@@ skipping 21 matching lines @@
     didAccess();
 
     return state.takeStyle();
 }
 
 // This function is used by the WebAnimations JavaScript API method animate().
 // FIXME: Remove this when animate() switches away from resolution-dependent parsing.
 PassRefPtrWillBeRawPtr<AnimatableValue> StyleResolver::createAnimatableValueSnapshot(Element& element, CSSPropertyID property, CSSValue& value)
 {
     RefPtr<LayoutStyle> style;
-    if (LayoutStyle* elementStyle = element.layoutStyle())
+    if (const LayoutStyle* elementStyle = element.layoutStyle())
         style = LayoutStyle::clone(*elementStyle);
     else
         style = LayoutStyle::create();
     StyleResolverState state(element.document(), &element);
     state.setStyle(style);
     return createAnimatableValueSnapshot(state, property, value);
 }
 
 PassRefPtrWillBeRawPtr<AnimatableValue> StyleResolver::createAnimatableValueSnapshot(StyleResolverState& state, CSSPropertyID property, CSSValue& value)
 {
@@ skipping 22 matching lines @@
 
     if (pseudoId == BACKDROP && !parent.isInTopLayer())
         return nullptr;
 
     if (pseudoId == FIRST_LETTER && (parent.isSVGElement() || !FirstLetterPseudoElement::firstLetterTextRenderer(parent)))
         return nullptr;
 
     if (!parentRenderer->canHaveGeneratedChildren())
         return nullptr;
 
-    LayoutStyle* parentStyle = parentRenderer->style();
-    if (LayoutStyle* cachedStyle = parentStyle->getCachedPseudoStyle(pseudoId)) {
+    LayoutStyle* parentStyle = parentRenderer->mutableStyle();
+    if (const LayoutStyle* cachedStyle = parentStyle->getCachedPseudoStyle(pseudoId)) {
         if (!pseudoElementRendererIsNeeded(cachedStyle))
             return nullptr;
         return createPseudoElement(&parent, pseudoId);
     }
 
     StyleResolverState state(document(), &parent, parentStyle);
     if (!pseudoStyleForElementInternal(parent, pseudoId, parentStyle, state))
         return nullptr;
     RefPtr<LayoutStyle> style = state.takeStyle();
     ASSERT(style);
     parentStyle->addCachedPseudoStyle(style);
 
     if (!pseudoElementRendererIsNeeded(style.get()))
         return nullptr;
 
     RefPtrWillBeRawPtr<PseudoElement> pseudo = createPseudoElement(&parent, pseudoId);
 
     setAnimationUpdateIfNeeded(state, *pseudo);
     if (ActiveAnimations* activeAnimations = pseudo->activeAnimations())
         activeAnimations->cssAnimations().maybeApplyPendingUpdate(pseudo.get());
     return pseudo.release();
 }
 
-bool StyleResolver::pseudoStyleForElementInternal(Element& element, const PseudoStyleRequest& pseudoStyleRequest, LayoutStyle* parentStyle, StyleResolverState& state)
+bool StyleResolver::pseudoStyleForElementInternal(Element& element, const PseudoStyleRequest& pseudoStyleRequest, const LayoutStyle* parentStyle, StyleResolverState& state)
 {
     ASSERT(document().frame());
     ASSERT(document().settings());
     ASSERT(pseudoStyleRequest.pseudoId != FIRST_LINE_INHERITED);
     ASSERT(state.parentStyle());
 
     StyleResolverParentScope::ensureParentStackIsPushed();
 
     Element* pseudoElement = element.pseudoElement(pseudoStyleRequest.pseudoId);
 
@@ skipping 48 matching lines @@
         adjustLayoutStyle(state, 0);
 
     didAccess();
 
     if (state.style()->hasViewportUnits())
         document().setHasViewportUnits();
 
     return true;
 }
 
-PassRefPtr<LayoutStyle> StyleResolver::pseudoStyleForElement(Element* element, const PseudoStyleRequest& pseudoStyleRequest, LayoutStyle* parentStyle)
+PassRefPtr<LayoutStyle> StyleResolver::pseudoStyleForElement(Element* element, const PseudoStyleRequest& pseudoStyleRequest, const LayoutStyle* parentStyle)
 {
     ASSERT(parentStyle);
     if (!element)
         return nullptr;
 
     StyleResolverState state(document(), element, parentStyle);
     if (!pseudoStyleForElementInternal(*element, pseudoStyleRequest, parentStyle, state)) {
         if (pseudoStyleRequest.type == PseudoStyleRequest::ForRenderer)
             return nullptr;
         return state.takeStyle();
@@ skipping 68 matching lines @@
     return style.release();
 }
 
 PassRefPtr<LayoutStyle> StyleResolver::styleForText(Text* textNode)
 {
     ASSERT(textNode);
 
     Node* parentNode = NodeRenderingTraversal::parent(*textNode);
     if (!parentNode || !parentNode->layoutStyle())
         return defaultStyleForElement();
-    return parentNode->layoutStyle();
+    return parentNode->mutableLayoutStyle();
 }
 
 void StyleResolver::updateFont(StyleResolverState& state)
 {
     state.fontBuilder().createFont(document().styleEngine()->fontSelector(), state.mutableStyleRef());
     state.setConversionFontSizes(CSSToLengthConversionData::FontSizes(state.style(), state.rootElementStyle()));
     state.setConversionZoom(state.style()->effectiveZoom());
 }
 
 PassRefPtrWillBeRawPtr<StyleRuleList> StyleResolver::styleRulesForElement(Element* element, unsigned rulesToInclude)
@@ skipping 583 matching lines @@
     visitor->trace(m_uncommonAttributeRuleSet);
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingRules);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);
     visitor->trace(m_document);
 #endif
 }
 
 } // namespace blink