Add CSS conic-gradient calc() support

third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 
 #include "core/css/CSSCalculationValue.h"
 #include "core/css/CSSColorValue.h"
 #include "core/css/CSSCrossfadeValue.h"
 #include "core/css/CSSGradientValue.h"
@@ skipping 922 matching lines @@
     result->AddStop(stop);
   }
 
   return result;
 }
 
 static CSSPrimitiveValue* ConsumeAngleOrPercent(CSSParserTokenRange& range,
                                                 CSSParserMode,
                                                 ValueRange value_range,
                                                 UnitlessQuirk) {
-  return range.Peek().GetType() == kPercentageToken
-             ? ConsumePercent(range, value_range)
-             : ConsumeAngle(range);
+  if (auto* css_percent = ConsumePercent(range, value_range))
+    return css_percent;
+  if (auto* css_angle = ConsumeAngle(range))
+    return css_angle;
+
+  return nullptr;
 }
 
 using PositionFunctor = CSSPrimitiveValue* (*)(CSSParserTokenRange&,
                                                CSSParserMode,
                                                ValueRange,
                                                UnitlessQuirk);
 
 static bool ConsumeGradientColorStops(CSSParserTokenRange& range,
                                       CSSParserMode css_parser_mode,
                                       CSSGradientValue* gradient,
@@ skipping 470 matching lines @@
 
 // https://drafts.csswg.org/css-shapes-1/#typedef-shape-box
 CSSIdentifierValue* ConsumeShapeBox(CSSParserTokenRange& range) {
   return ConsumeIdent<CSSValueContentBox, CSSValuePaddingBox, CSSValueBorderBox,
                       CSSValueMarginBox>(range);
 }
 
 }  // namespace CSSPropertyParserHelpers
 
 }  // namespace blink