Make RenderObject::style() return a const object

Source/core/layout/LayoutThemeChromiumMac.h

Index: Source/core/layout/LayoutThemeChromiumMac.h
diff --git a/Source/core/layout/LayoutThemeChromiumMac.h b/Source/core/layout/LayoutThemeChromiumMac.h
index 65845e720a4c55af026bde9f9d502ed6e39ff88f..6548149870dac190ef775e27520289d0b3b91c06 100644
--- a/Source/core/layout/LayoutThemeChromiumMac.h
+++ b/Source/core/layout/LayoutThemeChromiumMac.h
@@ -56,7 +56,7 @@ public:
     // System fonts.
     virtual void systemFont(CSSValueID systemFontID, FontStyle&, FontWeight&, float& fontSize, AtomicString& fontFamily) const override;
 
-    virtual int minimumMenuListSize(RenderStyle*) const override;
+    virtual int minimumMenuListSize(const RenderStyle*) const override;
 
     virtual void adjustSliderThumbSize(RenderStyle*, Element*) const override;
 
@@ -126,8 +126,8 @@ private:
     FloatRect convertToPaintingRect(const RenderObject* inputRenderer, const RenderObject* partRenderer, const FloatRect& inputRect, const IntRect&) const;
 
     // Get the control size based off the font. Used by some of the controls (like buttons).
-    NSControlSize controlSizeForFont(RenderStyle*) const;
-    NSControlSize controlSizeForSystemFont(RenderStyle*) const;
+    NSControlSize controlSizeForFont(const RenderStyle*) const;
+    NSControlSize controlSizeForSystemFont(const RenderStyle*) const;
     void setControlSize(NSCell*, const IntSize* sizes, const IntSize& minSize, float zoomLevel = 1.0f);
     void setSizeFromFont(RenderStyle*, const IntSize* sizes) const;
     IntSize sizeForFont(RenderStyle*, const IntSize* sizes) const;
@@ -160,7 +160,7 @@ private:
     NSLevelIndicatorStyle levelIndicatorStyleFor(ControlPart) const;
     NSLevelIndicatorCell* levelIndicatorFor(const RenderMeter*) const;
 
-    int minimumProgressBarHeight(RenderStyle*) const;
+    int minimumProgressBarHeight(const RenderStyle*) const;
     const IntSize* progressBarSizes() const;
     const int* progressBarMargins(NSControlSize) const;