Include a machine id in log files.

ui/file_manager/file_manager/common/js/unittest_util.js

Index: ui/file_manager/file_manager/common/js/unittest_util.js
diff --git a/ui/file_manager/file_manager/common/js/unittest_util.js b/ui/file_manager/file_manager/common/js/unittest_util.js
index a47b43b6228730ab50af551ea19ae9f91b04055e..21629948763806761ed15d7b88b6414e548d7d0f 100644
--- a/ui/file_manager/file_manager/common/js/unittest_util.js
+++ b/ui/file_manager/file_manager/common/js/unittest_util.js
@@ -200,12 +200,13 @@ function MockChromeStorageAPI() {
  * @private
  */
 MockChromeStorageAPI.prototype.get_ = function(keys, callback) {
-  var keyArray = keys instanceof Array ? keys : [keys];
+  var keys = keys instanceof Array ? keys : [keys];
   var result = {};
-  for (var key in keys) {
-    if (key in this.state)
-      result[key] = this.state[key];
-  }
+  keys.forEach(
+      function(key) {
+        if (key in this.state)
+          result[key] = this.state[key];
+      }.bind(this));
   callback(result);
 };