Make RenderObject::style() return a const object

Source/core/layout/LayoutObject.cpp

Index: Source/core/layout/LayoutObject.cpp
diff --git a/Source/core/layout/LayoutObject.cpp b/Source/core/layout/LayoutObject.cpp
index 673b5f869d1d61c1b81de420eab58e240e82ae8b..9fd743eb11281c4c64ebbb98df8a47b9420cbb49 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -2624,11 +2624,11 @@ static PassRefPtr<LayoutStyle> firstLineStyleForCachedUncachedType(StyleCacheSta
         }
     } else if (!rendererForFirstLineStyle->isAnonymous() && rendererForFirstLineStyle->isRenderInline()
         && !rendererForFirstLineStyle->node()->isFirstLetterPseudoElement()) {
-        LayoutStyle* parentStyle = rendererForFirstLineStyle->parent()->firstLineStyle();
+        const LayoutStyle* parentStyle = rendererForFirstLineStyle->parent()->firstLineStyle();
         if (parentStyle != rendererForFirstLineStyle->parent()->style()) {
             if (type == Cached) {
                 // A first-line style is in effect. Cache a first-line style for ourselves.
-                rendererForFirstLineStyle->style()->setHasPseudoStyle(FIRST_LINE_INHERITED);
+                rendererForFirstLineStyle->mutableStyle()->setHasPseudoStyle(FIRST_LINE_INHERITED);
                 return rendererForFirstLineStyle->getCachedPseudoStyle(FIRST_LINE_INHERITED, parentStyle);
             }
             return rendererForFirstLineStyle->getUncachedPseudoStyle(PseudoStyleRequest(FIRST_LINE_INHERITED), parentStyle, style);
@@ -2657,7 +2657,7 @@ LayoutStyle* LayoutObject::cachedFirstLineStyle() const
     return m_style.get();
 }
 
-LayoutStyle* LayoutObject::getCachedPseudoStyle(PseudoId pseudo, LayoutStyle* parentStyle) const
+LayoutStyle* LayoutObject::getCachedPseudoStyle(PseudoId pseudo, const LayoutStyle* parentStyle) const
 {
     if (pseudo < FIRST_INTERNAL_PSEUDOID && !style()->hasPseudoStyle(pseudo))
         return 0;
@@ -2668,11 +2668,11 @@ LayoutStyle* LayoutObject::getCachedPseudoStyle(PseudoId pseudo, LayoutStyle* pa
 
     RefPtr<LayoutStyle> result = getUncachedPseudoStyle(PseudoStyleRequest(pseudo), parentStyle);
     if (result)
-        return style()->addCachedPseudoStyle(result.release());
+        return mutableStyle()->addCachedPseudoStyle(result.release());
     return 0;
 }
 
-PassRefPtr<LayoutStyle> LayoutObject::getUncachedPseudoStyle(const PseudoStyleRequest& pseudoStyleRequest, LayoutStyle* parentStyle, LayoutStyle* ownStyle) const
+PassRefPtr<LayoutStyle> LayoutObject::getUncachedPseudoStyle(const PseudoStyleRequest& pseudoStyleRequest, const LayoutStyle* parentStyle, const LayoutStyle* ownStyle) const
 {
     if (pseudoStyleRequest.pseudoId < FIRST_INTERNAL_PSEUDOID && !ownStyle && !style()->hasPseudoStyle(pseudoStyleRequest.pseudoId))
         return nullptr;
@@ -2717,7 +2717,7 @@ PassRefPtr<LayoutStyle> LayoutObject::getUncachedPseudoStyleFromParentOrShadowHo
 void LayoutObject::getTextDecorations(unsigned decorations, AppliedTextDecoration& underline, AppliedTextDecoration& overline, AppliedTextDecoration& linethrough, bool quirksMode, bool firstlineStyle)
 {
     LayoutObject* curr = this;
-    LayoutStyle* styleToUse = 0;
+    const LayoutStyle* styleToUse = 0;
     unsigned currDecs = TextDecorationNone;
     Color resultColor;
     TextDecorationStyle resultStyle;