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

Source/core/css/CSSPrimitiveValueMappings.h

Index: Source/core/css/CSSPrimitiveValueMappings.h
diff --git a/Source/core/css/CSSPrimitiveValueMappings.h b/Source/core/css/CSSPrimitiveValueMappings.h
index 2d41b489175f319696eeef04bdfe4f313e762900..b8aa6776015aa55860e2b64b67d74b51ff54fe92 100644
--- a/Source/core/css/CSSPrimitiveValueMappings.h
+++ b/Source/core/css/CSSPrimitiveValueMappings.h
@@ -1935,36 +1935,6 @@ template<> inline CSSPrimitiveValue::operator EMarqueeBehavior() const
     return MNONE;
 }
 
-template<> inline CSSPrimitiveValue::CSSPrimitiveValue(RegionFragment e)
-    : CSSValue(PrimitiveClass)
-{
-    m_primitiveUnitType = CSS_VALUE_ID;
-    switch (e) {
-    case AutoRegionFragment:
-        m_value.valueID = CSSValueAuto;
-        break;
-    case BreakRegionFragment:
-        m_value.valueID = CSSValueBreak;
-        break;
-    }
-}
-
-template<> inline CSSPrimitiveValue::operator RegionFragment() const
-{
-    ASSERT(isValueID());
-    switch (m_value.valueID) {
-    case CSSValueAuto:
-        return AutoRegionFragment;
-    case CSSValueBreak:
-        return BreakRegionFragment;
-    default:
-        break;
-    }
-
-    ASSERT_NOT_REACHED();
-    return AutoRegionFragment;
-}
-
 template<> inline CSSPrimitiveValue::CSSPrimitiveValue(EMarqueeDirection e)
     : CSSValue(PrimitiveClass)
 {