Remove CSS_REGIONS compile flag from Blink.

Source/core/css/WebKitCSSRegionRule.h

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
@@ skipping 15 matching lines @@
  * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #ifndef WebKitCSSRegionRule_h
 #define WebKitCSSRegionRule_h
 
 #include "core/css/CSSGroupingRule.h"
 
-#if ENABLE(CSS_REGIONS)
-
 namespace WebCore {
 
 class StyleRuleRegion;
 
 class WebKitCSSRegionRule : public CSSGroupingRule {
 public:
     static PassRefPtr<WebKitCSSRegionRule> create(StyleRuleRegion* rule, CSSStyleSheet* sheet) { return adoptRef(new WebKitCSSRegionRule(rule, sheet)); }
 
     virtual CSSRule::Type type() const OVERRIDE { return WEBKIT_REGION_RULE; }
     virtual String cssText() const OVERRIDE;
 
 private:
     WebKitCSSRegionRule(StyleRuleRegion*, CSSStyleSheet* parent);
 };
 
 }
 
-#endif // ENABLE(CSS_REGIONS)
-
 #endif // WebKitCSSRegionRule_h