Update chrome.metricsPrivate externs and make closure fixes

remoting/webapp/js_proto/chrome_mocks.js

 // Copyright 2014 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.
 
 // This file contains various mock objects for the chrome platform to make
 // unit testing easier.
 
 var chromeMocks = {};
 
 (function(){
@@ skipping 231 matching lines @@
 chromeMocks.Identity.prototype.mock$clearToken = function() {
   this.token_ = undefined;
 };
 
 /** @type {chromeMocks.Identity} */
 chromeMocks.identity;
 
 /** @constructor */
 chromeMocks.MetricsPrivate = function() {};
 
+chromeMocks.MetricsPrivate.prototype.MetricTypeType = {
+  HISTOGRAM_LOG: 'histogram-log',
+  HISTOGRAM_LINEAR: 'histogram-linear',
+};
+
 chromeMocks.MetricsPrivate.prototype.recordValue = function() {};
 
 /** @type {chromeMocks.MetricsPrivate} */
 chromeMocks.metricsPrivate;
 
 /** @constructor */
 chromeMocks.I18n = function() {};
 
 /**
  * @param {string} messageName
@@ skipping 52 matching lines @@
     throw new Error('You must call activate() before restore().');
   }
   for (var components in originals_) {
     chrome[components] = originals_[components];
   }
   originals_ = null;
   nativePorts = null;
 };
 
 })();