Fix trivial type-check errors in file_manager.

ui/file_manager/file_manager/foreground/js/metrics.js

 // Copyright (c) 2012 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.
 
 /**
  * @fileoverview Utility methods for accessing chrome.metricsPrivate API.
  *
  * To be included as a first script in main.html
  */
 
@@ skipping 76 matching lines @@
     metrics.recordTime(name, Date.now() - metrics.intervals[name]);
   } else {
     console.error('Unknown interval: ' + name);
   }
 };
 
 /**
  * Record an enum value.
  *
  * @param {string} name Metric name.
- * @param {Object} value Enum value.
- * @param {Array.<Object>|number} validValues Array of valid values
+ * @param {*} value Enum value.
+ * @param {Array.<*>|number} validValues Array of valid values
  *                                            or a boundary number value.
  */
 metrics.recordEnum = function(name, value, validValues) {
   var boundaryValue;
   var index;
   if (validValues.constructor.name == 'Array') {
     index = validValues.indexOf(value);
     boundaryValue = validValues.length;
   } else {
-    index = value;
+    index = /** @type {number} */ (value);
     boundaryValue = validValues;
   }
   // Collect invalid values in the overflow bucket at the end.
   if (index < 0 || index > boundaryValue)
     index = boundaryValue;
 
   // Setting min to 1 looks strange but this is exactly the recommended way
   // of using histograms for enum-like types. Bucket #0 works as a regular
   // bucket AND the underflow bucket.
   // (Source: UMA_HISTOGRAM_ENUMERATION definition in base/metrics/histogram.h)
   var metricDescr = {
     'metricName': metrics.convertName_(name),
     'type': 'histogram-linear',
     'min': 1,
     'max': boundaryValue,
     'buckets': boundaryValue + 1
   };
   metrics.call_('recordValue', [metricDescr, index]);
   if (metrics.log) {
     console.log('chrome.metricsPrivate.recordValue',
         [metricDescr.metricName, index, value]);
   }
 };