Add UMA stats for storage manager for Chrome OS.

chrome/browser/resources/options/chromeos/storage_manager.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.
 
 /**
  * Enumeration for device state about remaining space.
  * These values must be kept in sync with
  * StorageManagerHandler::StorageSpaceState in C++ code.
  * @enum {number}
  * @const
@@ skipping 35 matching lines @@
      * @private {number}
      */
     updateTimerId_: -1,
 
     /** @override */
     initializePage: function() {
       Page.prototype.initializePage.call(this);
 
       $('storage-manager-label-downloads').onclick = function() {
         chrome.send('openDownloads');
+        chrome.send('coreOptionsUserMetricsAction',
+                    ['Options_StorageOpenDownloads']);
       };
       $('storage-manager-label-drive-cache').onclick = function() {
         PageManager.showPageByName('storageClearDriveCache');
+        chrome.send('coreOptionsUserMetricsAction',
+                    ['Options_StorageOpenClearDriveCache']);
       };
       $('storage-manager-label-browsing-data').onclick = function() {
         PageManager.showPageByName('clearBrowserData');
+        chrome.send('coreOptionsUserMetricsAction',
+                    ['Options_StorageOpenClearBrowsingData']);
       };
       $('storage-manager-label-arc').onclick = function() {
         chrome.send('openArcStorage');
+        chrome.send('coreOptionsUserMetricsAction',
+                    ['Options_StorageOpenAndroidStorage']);
       };
       $('storage-manager-label-other-users').onclick = function() {
         PageManager.showPageByName('accounts');
+        chrome.send('coreOptionsUserMetricsAction',
+                    ['Options_StorageOpenAccounts']);
       };
 
       $('storage-confirm').onclick = function() {
         PageManager.closeOverlay();
       };
     },
 
     /** @override */
     didShowPage: function() {
       // Updating storage information can be expensive (e.g. computing directory
@@ skipping 116 matching lines @@
     'setDriveCacheSize',
     'setOtherUsersSize',
     'setSizeStat',
     'showArcItem',
   ]);
 
   return {
     StorageManager: StorageManager
   };
 });