Add utility for looping from 0 to n.

Closes #1518

Change-Id: I865f7a0311516d04ae84532dab873e1aaa31eb24

lib/util/string_utils.js

@@ -110,7 +110,7 @@ shaka.util.StringUtils = class {
     const length = Math.floor(data.byteLength / 2);
     const arr = new Uint16Array(length);
     const dataView = new DataView(buffer);
-    for (let i = 0; i < length; i++) {
+    for (const i of shaka.util.Iterables.range(length)) {
       arr[i] = dataView.getUint16(i * 2, littleEndian);
     }
     return shaka.util.StringUtils.fromCharCode(arr);