Mojo JS bindings: make sure that console.log() could be used in the bindings.

ios/web/webui/resources/console.js

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Module "console"
+//
+// This module provides basic logging support. The reason to define this module
+// to forward calls to the |console| object exposed by the browser, instead of
+// using that object directly: mojo JS bindings are currently loaded using gin
+// and the |console| object is not always available. When the Mojo JS bindings
+// move away from gin, this module could be removed.
+
+define("console", [], function() {
+  /**
+   * Logs a message to the console.
+   * @param {string} message to log.
+   */
+  function log(message) {
+    console.log(message);
+  }
+
+  var exports = {};
+  exports.log = log;
+  return exports;
+});