message: Remove  the needless checking for `orig`
  In Texture , the `orig` is always exist after new Texture object .
  If `orig` is not accessible , there will be a bug in the App.
  The developers must fix it , not ignore and return `0`.
diff: @@ -517,7 +517,7 @@ export default class Texture extends EventEmitter
  */
  get width()
  {
  - return this.orig ? this.orig.width : 0;
  + return this.orig.width;
  }
  /**
  @@ -527,7 +527,7 @@ export default class Texture extends EventEmitter
  */
  get height()
  {
  - return this.orig ? this.orig.height : 0;
  + return this.orig.height;
  }
  }
  