Support animating <resolution> custom properties

third_party/WebKit/Source/core/css/CSSPrimitiveValue.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2012 Apple Inc. All rights
  * reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 247 matching lines @@
     case UnitType::kGradians:
       return grad2deg(GetDoubleValue());
     case UnitType::kTurns:
       return turn2deg(GetDoubleValue());
     default:
       NOTREACHED();
       return 0;
   }
 }
 
+double CSSPrimitiveValue::ComputeDotsPerPixel() const {
+  UnitType current_type = TypeWithCalcResolved();
+  DCHECK(IsResolution(current_type));
+  return GetDoubleValue() * ConversionToCanonicalUnitsScaleFactor(current_type);
+}
+
 template <>
 int CSSPrimitiveValue::ComputeLength(
     const CSSToLengthConversionData& conversion_data) const {
   return RoundForImpreciseConversion<int>(ComputeLengthDouble(conversion_data));
 }
 
 template <>
 unsigned CSSPrimitiveValue::ComputeLength(
     const CSSToLengthConversionData& conversion_data) const {
   return RoundForImpreciseConversion<unsigned>(
@@ skipping 437 matching lines @@
     case UnitType::kCalc:
       visitor->Trace(value_.calc);
       break;
     default:
       break;
   }
   CSSValue::TraceAfterDispatch(visitor);
 }
 
 }  // namespace blink