Implements CSSPropertyAPI for the column-count property.

third_party/WebKit/Source/core/css/CSSProperties.json5

 {
 // This file specifies all the CSS properties we support and the necessary
 // information for our code generation. The various supported arguments
 // are described below with example usage
 
   parameters: {
     // - alias_for: "other-property"
     // Properties specifying alias_for should be virtually identical to the
     // properties they alias. Minor parsing differences are allowed as long as
     // the CSSValues created are of the same format of the aliased property.
@@ skipping 1904 matching lines @@
       type_name: "unsigned int",
     },
     "-webkit-box-orient",
     "-webkit-box-pack",
     {
       name: "-webkit-box-reflect",
       converter: "convertBoxReflect",
     },
     {
       name: "column-count",
+      api_class: true,
+      api_methods: ["parseSingleValue"],
       custom_all: true,
       interpolable: true,
       type_name: "unsigned short",
     },
     {
       name: "column-gap",
       api_class: true,
       api_methods: ["parseSingleValue"],
       converter: "convertComputedLength<float>",
       custom_all: true,
@@ skipping 1023 matching lines @@
     {
       name: "-webkit-transition-timing-function",
       alias_for: "transition-timing-function",
     },
     {
       name: "-webkit-user-select",
       alias_for: "user-select",
     },
   ],
 }