Remove CSS regions support, keeping a bare minimum to support "region-based" multicol.

Source/core/css/resolver/StyleResolverState.h

Index: Source/core/css/resolver/StyleResolverState.h
diff --git a/Source/core/css/resolver/StyleResolverState.h b/Source/core/css/resolver/StyleResolverState.h
index f16016c40792987c5093d6683f7a5c8592b9190a..9c93a43e11a3d8a065c2e834242ffad68fdea068 100644
--- a/Source/core/css/resolver/StyleResolverState.h
+++ b/Source/core/css/resolver/StyleResolverState.h
@@ -39,13 +39,12 @@ namespace WebCore {
 
 class CSSAnimationUpdate;
 class FontDescription;
-class RenderRegion;
 class StyleRule;
 
 class StyleResolverState {
 WTF_MAKE_NONCOPYABLE(StyleResolverState);
 public:
-    StyleResolverState(Document&, Element*, RenderStyle* parentStyle = 0, RenderRegion* regionForStyling = 0);
+    StyleResolverState(Document&, Element*, RenderStyle* parentStyle = 0);
     ~StyleResolverState();
 
     // In FontFaceSet and CanvasRenderingContext2D, we don't have an element to grab the document from.
@@ -75,8 +74,6 @@ public:
     const RenderStyle* parentStyle() const { return m_parentStyle.get(); }
     RenderStyle* parentStyle() { return m_parentStyle.get(); }
 
-    const RenderRegion* regionForStyling() const { return m_regionForStyling; }
-
     void setCurrentRule(StyleRule* currentRule) { m_currentRule = currentRule; }
     const StyleRule* currentRule() const { return m_currentRule; }
 
@@ -150,11 +147,6 @@ private:
 
     OwnPtr<CSSAnimationUpdate> m_animationUpdate;
 
-    // Required to ASSERT in applyProperties.
-    // FIXME: Regions should not need special state on StyleResolverState
-    // no other @rule does.
-    RenderRegion* m_regionForStyling;
-
     bool m_applyPropertyToRegularStyle;
     bool m_applyPropertyToVisitedLinkStyle;