Make RenderObject::style() return a const object

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index ada9f62818f3ec4ab276f8f0e3d05647a38aa019..8ac858abd2312551ef00df5cc04ae3c3642e6415 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -539,7 +539,7 @@ void StyleResolver::loadPendingResources(StyleResolverState& state)
     document().styleEngine()->fontSelector()->fontLoader()->loadPendingFonts();
 }
 
-PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderStyle* defaultParent, StyleSharingBehavior sharingBehavior,
+PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, const RenderStyle* defaultParent, StyleSharingBehavior sharingBehavior,
     RuleMatchingBehavior matchingBehavior)
 {
     ASSERT(document().frame());
@@ -596,7 +596,7 @@ PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderS
     // be propagated from shadow host to distributed node.
     if (state.distributedToInsertionPoint()) {
         if (Element* parent = element->parentElement()) {
-            if (RenderStyle* styleOfShadowHost = parent->renderStyle())
+            if (RenderStyle* styleOfShadowHost = parent->mutableRenderStyle())

[andersr, 2015/01/29 18:10:07]

We can use a const RenderStyle here?

                 state.style()->setUserModify(styleOfShadowHost->userModify());
         }
     }
@@ -660,7 +660,7 @@ PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderS
     return state.takeStyle();
 }
 
-PassRefPtr<RenderStyle> StyleResolver::styleForKeyframe(Element& element, const RenderStyle& elementStyle, RenderStyle* parentStyle, const StyleRuleKeyframe* keyframe, const AtomicString& animationName)
+PassRefPtr<RenderStyle> StyleResolver::styleForKeyframe(Element& element, const RenderStyle& elementStyle, const RenderStyle* parentStyle, const StyleRuleKeyframe* keyframe, const AtomicString& animationName)
 {
     ASSERT(document().frame());
     ASSERT(document().settings());
@@ -745,8 +745,9 @@ PassRefPtrWillBeRawPtr<PseudoElement> StyleResolver::createPseudoElementIfNeeded
     if (!parentRenderer->canHaveGeneratedChildren())
         return nullptr;
 
-    RenderStyle* parentStyle = parentRenderer->style();
-    if (RenderStyle* cachedStyle = parentStyle->getCachedPseudoStyle(pseudoId)) {
+    // Required for addCachedPseudoStyle, should probably make it logical const.
+    RenderStyle* parentStyle = parentRenderer->deprecatedMutableStyle();
+    if (const RenderStyle* cachedStyle = parentStyle->getCachedPseudoStyle(pseudoId)) {
         if (!pseudoElementRendererIsNeeded(cachedStyle))
             return nullptr;
         return createPseudoElement(&parent, pseudoId);
@@ -770,7 +771,7 @@ PassRefPtrWillBeRawPtr<PseudoElement> StyleResolver::createPseudoElementIfNeeded
     return pseudo.release();
 }
 
-bool StyleResolver::pseudoStyleForElementInternal(Element& element, const PseudoStyleRequest& pseudoStyleRequest, RenderStyle* parentStyle, StyleResolverState& state)
+bool StyleResolver::pseudoStyleForElementInternal(Element& element, const PseudoStyleRequest& pseudoStyleRequest, const RenderStyle* parentStyle, StyleResolverState& state)
 {
     ASSERT(document().frame());
     ASSERT(document().settings());
@@ -839,7 +840,7 @@ bool StyleResolver::pseudoStyleForElementInternal(Element& element, const Pseudo
     return true;
 }
 
-PassRefPtr<RenderStyle> StyleResolver::pseudoStyleForElement(Element* element, const PseudoStyleRequest& pseudoStyleRequest, RenderStyle* parentStyle)
+PassRefPtr<RenderStyle> StyleResolver::pseudoStyleForElement(Element* element, const PseudoStyleRequest& pseudoStyleRequest, const RenderStyle* parentStyle)
 {
     ASSERT(parentStyle);
     if (!element)
@@ -928,7 +929,7 @@ PassRefPtr<RenderStyle> StyleResolver::styleForText(Text* textNode)
     Node* parentNode = NodeRenderingTraversal::parent(*textNode);
     if (!parentNode || !parentNode->renderStyle())
         return defaultStyleForElement();
-    return parentNode->renderStyle();
+    return parentNode->mutableRenderStyle();
 }
 
 void StyleResolver::updateFont(StyleResolverState& state)