Make SVGLengthMode an enum class

Source/core/svg/SVGFilterElement.cpp

Index: Source/core/svg/SVGFilterElement.cpp
diff --git a/Source/core/svg/SVGFilterElement.cpp b/Source/core/svg/SVGFilterElement.cpp
index ffbd060835fa58170bc0bf9faabac9a6537f01ee..a6b4bbe382047988ec9154fddabd01226e1c2574 100644
--- a/Source/core/svg/SVGFilterElement.cpp
+++ b/Source/core/svg/SVGFilterElement.cpp
@@ -33,10 +33,10 @@ namespace blink {
 
 inline SVGFilterElement::SVGFilterElement(Document& document)
     : SVGElement(SVGNames::filterTag, document)
-    , m_x(SVGAnimatedLength::create(this, SVGNames::xAttr, SVGLength::create(LengthModeWidth), AllowNegativeLengths))
-    , m_y(SVGAnimatedLength::create(this, SVGNames::yAttr, SVGLength::create(LengthModeHeight), AllowNegativeLengths))
-    , m_width(SVGAnimatedLength::create(this, SVGNames::widthAttr, SVGLength::create(LengthModeWidth), ForbidNegativeLengths))
-    , m_height(SVGAnimatedLength::create(this, SVGNames::heightAttr, SVGLength::create(LengthModeHeight), ForbidNegativeLengths))
+    , m_x(SVGAnimatedLength::create(this, SVGNames::xAttr, SVGLength::create(SVGLengthMode::Width), AllowNegativeLengths))
+    , m_y(SVGAnimatedLength::create(this, SVGNames::yAttr, SVGLength::create(SVGLengthMode::Height), AllowNegativeLengths))
+    , m_width(SVGAnimatedLength::create(this, SVGNames::widthAttr, SVGLength::create(SVGLengthMode::Width), ForbidNegativeLengths))
+    , m_height(SVGAnimatedLength::create(this, SVGNames::heightAttr, SVGLength::create(SVGLengthMode::Height), ForbidNegativeLengths))
     , m_filterUnits(SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>::create(this, SVGNames::filterUnitsAttr, SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX))
     , m_primitiveUnits(SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>::create(this, SVGNames::primitiveUnitsAttr, SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE))
     , m_filterRes(SVGAnimatedIntegerOptionalInteger::create(this, SVGNames::filterResAttr))