Fix trivial type-check errors in file_manager.

ui/file_manager/file_manager/background/js/volume_manager.js

Index: ui/file_manager/file_manager/background/js/volume_manager.js
diff --git a/ui/file_manager/file_manager/background/js/volume_manager.js b/ui/file_manager/file_manager/background/js/volume_manager.js
index 64300d2f7a3f9b884469102a92b31fb3563ac559..1f0704ac80dfb4375f5a09f07678bb1a8b8cdbdb 100644
--- a/ui/file_manager/file_manager/background/js/volume_manager.js
+++ b/ui/file_manager/file_manager/background/js/volume_manager.js
@@ -11,18 +11,18 @@
  * @param {VolumeManagerCommon.VolumeType} volumeType The type of the volume.
  * @param {string} volumeId ID of the volume.
  * @param {FileSystem} fileSystem The file system object for this volume.
- * @param {string} error The error if an error is found.
- * @param {?string} deviceType The type of device ('usb'|'sd'|'optical'|'mobile'
- *     |'unknown') (as defined in chromeos/disks/disk_mount_manager.cc).
- *     Can be null.
- * @param {?string} devicePath Identifier of the device that the volume belongs
- *     to. Can be null.
+ * @param {(string|undefined)} error The error if an error is found.
+ * @param {(string|undefined)} deviceType The type of device
+ *     ('usb'|'sd'|'optical'|'mobile'|'unknown') (as defined in
+ *     chromeos/disks/disk_mount_manager.cc). Can be undefined.
+ * @param {(string|undefined)} devicePath Identifier of the device that the
+ *     volume belongs to. Can be undefined.
  * @param {boolean} isReadOnly True if the volume is read only.
  * @param {!{displayName:string, isCurrentProfile:boolean}} profile Profile
  *     information.
  * @param {string} label Label of the volume.
- * @param {string} extensionId Id of the extension providing this volume. Empty
- *     for native volumes.
+ * @param {(string|undefined)} extensionId Id of the extension providing this
+ *     volume. Empty for native volumes.
  * @constructor
  */
 function VolumeInfo(
@@ -110,19 +110,19 @@ VolumeInfo.prototype = {
     return this.fakeEntries_;
   },
   /**
-   * @return {string} Error identifier.
+   * @return {(string|undefined)} Error identifier.
    */
   get error() {
     return this.error_;
   },
   /**
-   * @return {string} Device type identifier.
+   * @return {(string|undefined)} Device type identifier.
    */
   get deviceType() {
     return this.deviceType_;
   },
   /**
-   * @return {string} Device identifier.
+   * @return {(string|undefined)} Device identifier.
    */
   get devicePath() {
     return this.devicePath_;
@@ -146,7 +146,7 @@ VolumeInfo.prototype = {
     return this.label_;
   },
   /**
-   * @return {string} Id of an extennsion providing this volume.
+   * @return {(string|undefined)} Id of an extennsion providing this volume.
    */
   get extensionId() {
     return this.extensionId_;
@@ -198,8 +198,7 @@ var volumeManagerUtil = {};
  * Throws an Error when the given error is not in
  * VolumeManagerCommon.VolumeError.
  *
- * @param {VolumeManagerCommon.VolumeError} error Status string usually received
- *     from APIs.
+ * @param {string} error Status string usually received from APIs.
  */
 volumeManagerUtil.validateError = function(error) {
   for (var key in VolumeManagerCommon.VolumeError) {
@@ -239,7 +238,8 @@ volumeManagerUtil.createVolumeInfo = function(volumeMetadata, callback) {
         if (!fileSystem) {
           console.error('File system not found: ' + volumeMetadata.volumeId);
           callback(new VolumeInfo(
-              volumeMetadata.volumeType,
+              /** @type {VolumeManagerCommon.VolumeType} */
+              (volumeMetadata.volumeType),
               volumeMetadata.volumeId,
               null,  // File system is not found.
               volumeMetadata.mountCondition,
@@ -266,7 +266,8 @@ volumeManagerUtil.createVolumeInfo = function(volumeMetadata, callback) {
               });
         }
         callback(new VolumeInfo(
-            volumeMetadata.volumeType,
+            /** @type {VolumeManagerCommon.VolumeType} */
+            (volumeMetadata.volumeType),
             volumeMetadata.volumeId,
             fileSystem,
             volumeMetadata.mountCondition,
@@ -301,8 +302,8 @@ volumeManagerUtil.volumeListOrder_ = [
  * The volumes at first are compared by volume type in the order of
  * volumeListOrder_.  Then they are compared by volume ID.
  *
- * @param {VolumeInfo} volumeInfo1 Volume info to be compared.
- * @param {VolumeInfo} volumeInfo2 Volume info to be compared.
+ * @param {!VolumeInfo} volumeInfo1 Volume info to be compared.
+ * @param {!VolumeInfo} volumeInfo2 Volume info to be compared.
  * @return {number} Returns -1 if volume1 < volume2, returns 1 if volume2 >
  *     volume1, returns 0 if volume1 === volume2.
  * @private
@@ -332,7 +333,9 @@ function VolumeInfoList() {
    * @private
    */
   this.model_ = new cr.ui.ArrayDataModel([]);
-  this.model_.setCompareFunction(field, volumeManagerUtil.compareVolumeInfo_);
+  this.model_.setCompareFunction(field,
+                                 /** @type {function(*, *): number} */
+                                 (volumeManagerUtil.compareVolumeInfo_));
   this.model_.sort(field, 'asc');
 
   Object.freeze(this);
@@ -420,10 +423,10 @@ VolumeInfoList.prototype.findByEntry = function(entry) {
 
 /**
  * @param {number} index The index of the volume in the list.
- * @return {VolumeInfo} The VolumeInfo instance.
+ * @return {!VolumeInfo} The VolumeInfo instance.
  */
 VolumeInfoList.prototype.item = function(index) {
-  return this.model_.item(index);
+  return /** @type {!VolumeInfo} */ (this.model_.item(index));
 };
 
 /**
@@ -456,6 +459,11 @@ function VolumeManager() {
 
   // The status should be merged into VolumeManager.
   // TODO(hidehiko): Remove them after the migration.
+  /**
+   * Connection state of the Drive.
+   * @type {VolumeManagerCommon.DriveConnectionState}
+   * @private
+   */
   this.driveConnectionState_ = {
     type: VolumeManagerCommon.DriveConnectionType.OFFLINE,
     reason: VolumeManagerCommon.DriveConnectionReason.NO_SERVICE
@@ -468,7 +476,7 @@ function VolumeManager() {
 
 /**
  * Invoked when the drive connection status is changed.
- * @private_
+ * @private
  */
 VolumeManager.prototype.onDriveConnectionStatusChanged_ = function() {
   chrome.fileManagerPrivate.getDriveConnectionState(function(state) {
@@ -479,7 +487,7 @@ VolumeManager.prototype.onDriveConnectionStatusChanged_ = function() {
 
 /**
  * Returns the drive connection state.
- * @return {VolumeManagerCommon.DriveConnectionType} Connection type.
+ * @return {VolumeManagerCommon.DriveConnectionState} Connection state.
  */
 VolumeManager.prototype.getDriveConnectionState = function() {
   return this.driveConnectionState_;
@@ -520,11 +528,11 @@ VolumeManager.instancePromise_ = null;
 /**
  * Returns the VolumeManager instance asynchronously. If it is not created or
  * under initialization, it will waits for the finish of the initialization.
- * @param {function(VolumeManager)} callback Called with the VolumeManager
+ * @param {function(VolumeManager)=} opt_callback Called with the VolumeManager
  *     instance. TODO(hirono): Remove the callback and use Promise instead.
  * @return {Promise} Promise to be fulfilled with the volume manager.
  */
-VolumeManager.getInstance = function(callback) {
+VolumeManager.getInstance = function(opt_callback) {
   if (!VolumeManager.instancePromise_) {
     VolumeManager.instance_ = new VolumeManager();
     VolumeManager.instancePromise_ = new Promise(function(fulfill) {
@@ -533,8 +541,8 @@ VolumeManager.getInstance = function(callback) {
       });
     });
   }
-  if (callback)
-    VolumeManager.instancePromise_.then(callback);
+  if (opt_callback)
+    VolumeManager.instancePromise_.then(opt_callback);
   return VolumeManager.instancePromise_;
 };