Add smooth interpolation support for <length> custom properties

third_party/WebKit/Source/core/css/CSSSyntaxDescriptor.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/CSSSyntaxDescriptor.h"
 
 #include "core/animation/CSSColorInterpolationType.h"
+#include "core/animation/CSSLengthInterpolationType.h"
 #include "core/animation/CSSValueInterpolationType.h"
 #include "core/css/CSSCustomPropertyDeclaration.h"
 #include "core/css/CSSURIValue.h"
 #include "core/css/CSSValueList.h"
 #include "core/css/CSSVariableReferenceValue.h"
 #include "core/css/parser/CSSParserIdioms.h"
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 #include "core/css/parser/CSSVariableParser.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 
@@ skipping 204 matching lines @@
       // TODO(alancutter): Support animation of repeatable types.
       continue;
     }
 
     switch (component.m_type) {
       case CSSSyntaxType::Color:
         interpolationTypes.push_back(
             WTF::makeUnique<CSSColorInterpolationType>(property));
         break;
       case CSSSyntaxType::Length:
+        interpolationTypes.push_back(
+            WTF::makeUnique<CSSLengthInterpolationType>(property));
+        break;
       case CSSSyntaxType::Number:
       case CSSSyntaxType::Percentage:
       case CSSSyntaxType::LengthPercentage:
       case CSSSyntaxType::Image:
       case CSSSyntaxType::Url:
       case CSSSyntaxType::Integer:
       case CSSSyntaxType::Angle:
       case CSSSyntaxType::Time:
       case CSSSyntaxType::Resolution:
       case CSSSyntaxType::TransformFunction:
         // TODO(alancutter): Support smooth interpolation of these types.
         break;
       case CSSSyntaxType::TokenStream:
       case CSSSyntaxType::Ident:
       case CSSSyntaxType::CustomIdent:
         // Uses the CSSValueInterpolationType added below.
         break;
       default:
         NOTREACHED();
         break;
     }
   }
   interpolationTypes.push_back(
       WTF::makeUnique<CSSValueInterpolationType>(property));
   return interpolationTypes;
 }
 
 }  // namespace blink