Fix the tooltip for thumbnail view option in gallery on tabbing

ui/file_manager/gallery/js/gallery.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.
 
 /**
  * Overrided metadata worker's path.
  * @type {string}
  */
 ContentMetadataProvider.WORKER_SCRIPT = '/js/metadata_worker.js';
 
@@ skipping 519 matching lines @@
  * Change to slide mode.
  * @private
  */
 Gallery.prototype.onChangeToSlideMode_ = function() {
   if (this.modeSwitchButton_.disabled)
     return;
 
   this.changeCurrentMode_(this.slideMode_);
 };
 
+
+/**
+ * Update attributes of slide/thumbnail toggle button
+ * @param {Event=} event Event that caused this call
+ * @private
+*/

[oka, 2017/01/12 01:59:24]

Add a space before *.

[takise, 2017/01/12 04:08:05]

Done.

+

[oka, 2017/01/12 01:59:24]

Remove this empty line.

[takise, 2017/01/12 04:08:05]

Done.

+Gallery.prototype.updateModeButtonAttribute_ = function(event) {
+  var button = event.currentTarget;

[oka, 2017/01/12 01:59:24]

Are you sure that event is not undefined? If event is undefined, this line
causes error.
I guess you can use this.modeSwitchButton_ here instead.

[takise, 2017/01/12 04:08:05]

Done.

+  if (this.currentMode_ === this.slideMode_)
+    button.setAttribute("aria-label", str("GALLERY_SLIDE"));
+  else
+    button.setAttribute("aria-label", str("GALLERY_THUMBNAIL"));
+}
+
 /**
  * Change current mode.
  * @param {!(SlideMode|ThumbnailMode)} mode Target mode.
  * @param {Event=} opt_event Event that caused this call.
  * @return {!Promise} Resolved when mode has been changed.
  * @private
  */
 Gallery.prototype.changeCurrentMode_ = function(mode, opt_event) {
   return new Promise(function(fulfill, reject) {
     // Do not re-enter while changing the mode.
     if (this.currentMode_ === mode || this.changingMode_) {
       fulfill();
       return;
     }
 
     if (opt_event)
       this.onUserAction_();
 
     this.changingMode_ = true;
 
     var onModeChanged = function() {
       this.changingMode_ = false;
       fulfill();
     }.bind(this);
 
     var thumbnailIndex = Math.max(0, this.selectionModel_.selectedIndex);
     var thumbnailRect = ImageRect.createFromBounds(
         this.thumbnailMode_.getThumbnailRect(thumbnailIndex));
 
+    this.updateModeButtonAttribute_(opt_event);

[oka, 2017/01/12 01:59:24]

I think this line should be moved to setCurrentMode_.
The comment of setCurrentMode_ reads "Sets the current mode, update the UI.". It
looks the appropriate place to update the button attribute.

[takise, 2017/01/12 04:08:05]

Done.

+
     if (mode === this.thumbnailMode_) {
       this.setCurrentMode_(this.thumbnailMode_);
       this.slideMode_.leave(
           thumbnailRect,
           function() {
             // Show thumbnail mode and perform animation.
             this.thumbnailMode_.show();
             var fromRect = this.slideMode_.getSelectedImageRect();
             if (fromRect) {
               this.thumbnailMode_.performEnterAnimation(
@@ skipping 483 matching lines @@
  */
 var initializePromise =
     Promise.all([loadTimeDataPromise, volumeManagerPromise]).
     then(function(args) {
       var volumeManager = args[1];
       gallery = new Gallery(volumeManager);
     });
 
 // Loads entries.
 initializePromise.then(reload);