message: Port ColorInfo.
diff: /*---------------------------------------------------------------------------------------------
  | $Copyright: (c) 2018 Bentley Systems, Incorporated. All rights reserved. $
  *--------------------------------------------------------------------------------------------*/
  -/* Describes a primitive's basic color properties
  +
  +import { assert } from "@bentley/bentleyjs-core";
  +import { FloatPreMulRgba } from "./FloatRGBA";
  +import { ColorIndex } from "@bentley/imodeljs-common";
  +
  +/* Describes a primitive's basic color properties */
  export class ColorInfo {
  - public readonly uniform?: FloatPreMulRgba;
  - public readonly hasAlpha: boolean;
  + public readonly _uniform?: FloatPreMulRgba;
  + public readonly hasTranslucency: boolean;
  public constructor(arg: FloatPreMulRgba | ColorIndex) {
  if (arg instanceof FloatPreMulRgba) {
  - this.uniform = arg
  + this.hasTranslucency = arg.hasTranslucency;
  + this._uniform = arg;
  + } else {
  + this.hasTranslucency = arg.hasAlpha;
  + if (undefined !== arg.uniform) {
  + this._uniform = FloatPreMulRgba.fromColorDef(arg.uniform);
  + }
  + }
  + }
  +
  + public get isUniform() { return undefined !== this.uniform; }
  + public get isNonUniform() { return !this.isUniform; }
  + public get uniform(): FloatPreMulRgba { assert(this.isUniform); return this._uniform!; }
  }
  -*/
  