CSS Custom Properties: Angles do not support unitless 0

third_party/WebKit/Source/core/frame/UseCounter.h

 /*
  * Copyright (C) 2012 Google, 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 disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1590 matching lines @@
     kPluginInstanceAccessFromIsolatedWorld = 1996,
     kPluginInstanceAccessFromMainWorld = 1997,
     kRequestFullscreenForDialogElement = 1998,
     kRequestFullscreenForDialogElementInTopLayer = 1999,
     kShowModalForElementInFullscreenStack = 2000,
     kThreeValuedPositionBackground = 2001,
     kThreeValuedPositionBasicShape = 2002,
     kThreeValuedPositionGradient = 2003,
     kThreeValuedPositionObjectPosition = 2004,
     kThreeValuedPositionPerspectiveOrigin = 2005,
-    kUnitlessZeroAngleCustomProperty = 2006,
     kUnitlessZeroAngleFilter = 2007,
     kUnitlessZeroAngleGradient = 2008,
     kUnitlessZeroAngleOffsetRotate = 2009,
     kUnitlessZeroAngleTransform = 2010,
     kHTMLOListElementStartGetterReversedWithoutStartAttribute = 2011,
     kCredentialManagerPreventSilentAccess = 2012,
     kNetInfoEffectiveType = 2013,
 
     // Add new features immediately above this line. Don't change assigned
     // numbers of any item, and don't reuse removed slots.
@@ skipping 104 matching lines @@
     // Tracks what features/properties need to be reported to the legacy
     // histograms.
     BitVector feature_bits_;
     BitVector css_bits_;
   } legacy_counter_;
 };
 
 }  // namespace blink
 
 #endif  // UseCounter_h