Remove dead code related to compositing from Sky

sky/engine/core/rendering/style/RenderStyle.h

Index: sky/engine/core/rendering/style/RenderStyle.h
diff --git a/sky/engine/core/rendering/style/RenderStyle.h b/sky/engine/core/rendering/style/RenderStyle.h
index 0663c0c8c9944022099eebe5d6dcc891b722b8b7..5a468b9f7510ae987975ebe3c2938f6f3a375839 100644
--- a/sky/engine/core/rendering/style/RenderStyle.h
+++ b/sky/engine/core/rendering/style/RenderStyle.h
@@ -778,7 +778,6 @@ public:
     const Vector<CSSPropertyID>& willChangeProperties() const { return rareNonInheritedData->m_willChange->m_properties; }
     bool willChangeContents() const { return rareNonInheritedData->m_willChange->m_contents; }
     bool willChangeScrollPosition() const { return rareNonInheritedData->m_willChange->m_scrollPosition; }
-    bool hasWillChangeCompositingHint() const;
     bool subtreeWillChangeContents() const { return rareInheritedData->m_subtreeWillChangeContents; }
 
 // attribute setter methods
@@ -1120,9 +1119,6 @@ public:
     void setWillChangeScrollPosition(bool b) { SET_VAR(rareNonInheritedData.access()->m_willChange, m_scrollPosition, b); }
     void setSubtreeWillChangeContents(bool b) { SET_VAR(rareInheritedData, m_subtreeWillChangeContents, b); }
 
-    bool requiresAcceleratedCompositingForExternalReasons(bool b) { return rareNonInheritedData->m_requiresAcceleratedCompositingForExternalReasons; }
-    void setRequiresAcceleratedCompositingForExternalReasons(bool b) { SET_VAR(rareNonInheritedData, m_requiresAcceleratedCompositingForExternalReasons, b); }
-
     void setClipPath(PassRefPtr<ClipPathOperation> operation)
     {
         if (rareNonInheritedData->m_clipPath != operation)