Add support for the object-fit CSS property.

Source/core/css/CSSParser-in.cpp

Index: Source/core/css/CSSParser-in.cpp
diff --git a/Source/core/css/CSSParser-in.cpp b/Source/core/css/CSSParser-in.cpp
index d2486d94b2fe9aacdc49b106fca9c726afdd7f74..501e8490012600f9790653c693f6178ca49d0fc8 100644
--- a/Source/core/css/CSSParser-in.cpp
+++ b/Source/core/css/CSSParser-in.cpp
@@ -636,6 +636,12 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if ((valueID >= CSSValueDisc && valueID <= CSSValueKatakanaIroha) || valueID == CSSValueNone)
             return true;
         break;
+    case CSSPropertyObjectFit:
+        if (RuntimeEnabledFeatures::objectFitPositionEnabled()) {
+            if (valueID == CSSValueFill || valueID == CSSValueContain || valueID == CSSValueCover || valueID == CSSValueNone || valueID == CSSValueScaleDown)
+                return true;
+        }
+        break;
     case CSSPropertyOutlineStyle: // (<border-style> except hidden) | auto | inherit
         if (valueID == CSSValueAuto || valueID == CSSValueNone || (valueID >= CSSValueInset && valueID <= CSSValueDouble))
             return true;
@@ -944,6 +950,7 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyImageRendering:
     case CSSPropertyListStylePosition:
     case CSSPropertyListStyleType:
+    case CSSPropertyObjectFit:
     case CSSPropertyOutlineStyle:
     case CSSPropertyOverflowWrap:
     case CSSPropertyOverflowX:
@@ -2746,6 +2753,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyImageRendering:
     case CSSPropertyListStylePosition:
     case CSSPropertyListStyleType:
+    case CSSPropertyObjectFit:
     case CSSPropertyOutlineStyle:
     case CSSPropertyOverflowWrap:
     case CSSPropertyOverflowX: