message: Fix performance test failure waiting for first frame complete event
  Always request an update after decoding empty tiles. Currently if the
  the last tile decoded is empty the frame complete event will not fire
  even though all visible tiles are loaded.
diff: @@ -226,11 +226,11 @@ export class TileDataSource<TileType extends Tile> extends DataSource {
  : this.m_options.copyrightInfo;
  tile.setDecodedTile(tileLoader.decodedTile);
  - this.requestUpdate();
  } else {
  // empty tiles are traditionally ignored and don't need decode
  tile.forceHasGeometry(true);
  }
  + this.requestUpdate();
  });
  }
  