Make RenderObject::style() return a const object

Source/core/layout/LayoutThemeChromiumMac.mm

Index: Source/core/layout/LayoutThemeChromiumMac.mm
diff --git a/Source/core/layout/LayoutThemeChromiumMac.mm b/Source/core/layout/LayoutThemeChromiumMac.mm
index 66c6dc4b023da4b58883efbad0695b764c872214..66cb56c0209a7154f603a292b0a34e3944b050b5 100644
--- a/Source/core/layout/LayoutThemeChromiumMac.mm
+++ b/Source/core/layout/LayoutThemeChromiumMac.mm
@@ -585,7 +585,7 @@ void LayoutThemeChromiumMac::updatePressedState(NSCell* cell, const RenderObject
         [cell setHighlighted:pressed];
 }
 
-NSControlSize LayoutThemeChromiumMac::controlSizeForFont(RenderStyle* style) const
+NSControlSize LayoutThemeChromiumMac::controlSizeForFont(const RenderStyle* style) const
 {
     int fontSize = style->fontSize();
     if (fontSize >= 16)
@@ -598,7 +598,7 @@ NSControlSize LayoutThemeChromiumMac::controlSizeForFont(RenderStyle* style) con
 // We don't use controlSizeForFont() for search field decorations because it
 // needs to fit into the search field. The font size will already be modified by
 // setFontFromControlSize() called on the search field.
-static NSControlSize searchFieldControlSizeForFont(RenderStyle* style)
+static NSControlSize searchFieldControlSizeForFont(const RenderStyle* style)
 {
     int fontSize = style->fontSize();
     if (fontSize >= 13)
@@ -672,7 +672,7 @@ void LayoutThemeChromiumMac::setFontFromControlSize(RenderStyle* style, NSContro
         style->font().update(nullptr);
 }
 
-NSControlSize LayoutThemeChromiumMac::controlSizeForSystemFont(RenderStyle* style) const
+NSControlSize LayoutThemeChromiumMac::controlSizeForSystemFont(const RenderStyle* style) const
 {
     float fontSize = style->fontSize();
     float zoomLevel = style->effectiveZoom();
@@ -972,7 +972,7 @@ const int* LayoutThemeChromiumMac::progressBarMargins(NSControlSize controlSize)
     return margins[controlSize];
 }
 
-int LayoutThemeChromiumMac::minimumProgressBarHeight(RenderStyle* style) const
+int LayoutThemeChromiumMac::minimumProgressBarHeight(const RenderStyle* style) const
 {
     return sizeForSystemFont(style, progressBarSizes()).height();
 }
@@ -1214,7 +1214,7 @@ const IntSize* LayoutThemeChromiumMac::menuListSizes() const
     return sizes;
 }
 
-int LayoutThemeChromiumMac::minimumMenuListSize(RenderStyle* style) const
+int LayoutThemeChromiumMac::minimumMenuListSize(const RenderStyle* style) const
 {
     return sizeForSystemFont(style, menuListSizes()).width();
 }