*** DO NOT LAND *** Remove regions support, keeping a bare minimum to support "region-based"...

Source/core/rendering/RenderLayerClipper.h

Index: Source/core/rendering/RenderLayerClipper.h
diff --git a/Source/core/rendering/RenderLayerClipper.h b/Source/core/rendering/RenderLayerClipper.h
index de03e7d407befe420448b5a2e932e85ebe0731a0..1d6551af5fd80eb1fba5e50fff478f4e74c5d658 100644
--- a/Source/core/rendering/RenderLayerClipper.h
+++ b/Source/core/rendering/RenderLayerClipper.h
@@ -51,19 +51,16 @@
 namespace WebCore {
 
 class RenderLayer;
-class RenderRegion;
 
 struct ClipRectsContext {
-    ClipRectsContext(const RenderLayer* inRootLayer, RenderRegion* inRegion, ClipRectsType inClipRectsType, OverlayScrollbarSizeRelevancy inOverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize, ShouldRespectOverflowClip inRespectOverflowClip = RespectOverflowClip, const LayoutSize& inSubPixelAccumulation = LayoutSize())
+    ClipRectsContext(const RenderLayer* inRootLayer, ClipRectsType inClipRectsType, OverlayScrollbarSizeRelevancy inOverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize, ShouldRespectOverflowClip inRespectOverflowClip = RespectOverflowClip, const LayoutSize& inSubPixelAccumulation = LayoutSize())
         : rootLayer(inRootLayer)
-        , region(inRegion)
         , clipRectsType(inClipRectsType)
         , overlayScrollbarSizeRelevancy(inOverlayScrollbarSizeRelevancy)
         , respectOverflowClip(inRespectOverflowClip)
         , subPixelAccumulation(inSubPixelAccumulation)
     { }
     const RenderLayer* rootLayer;
-    RenderRegion* region;
     ClipRectsType clipRectsType;
     OverlayScrollbarSizeRelevancy overlayScrollbarSizeRelevancy;
     ShouldRespectOverflowClip respectOverflowClip;