Generalize PreviewPanelModel so that it stops to refer specific cloud-import CSS class.

BUG=438947
TEST=FileManagerJsTest.PreviewPanelModelTest

Review URL: https://codereview.chromium.org/871563002

Cr-Commit-Position: refs/heads/master@{#312682}

ui/file_manager/file_manager/foreground/js/preview_panel_model.js

@@ -23,9 +23,9 @@ function PreviewPanelModel(initialVisibilityType) {
    * @const
    * @private
    */
-  this.cloudImportCommands_ = Array.prototype.slice.call(
-      document.querySelectorAll('command.cloud-import'));
-  cr.ui.decorate('command.cloud-import', cr.ui.Command);
+  this.autoVisibilityCommands_ = Array.prototype.slice.call(
+      document.querySelectorAll('command.auto-visibility'));
+  cr.ui.decorate('command.auto-visibility', cr.ui.Command);
 
   /**
    * FileSelection to be displayed.
@@ -42,8 +42,8 @@ function PreviewPanelModel(initialVisibilityType) {
    */
   this.visible = false;
 
-  for (var i = 0; i < this.cloudImportCommands_.length; i++) {
-    this.cloudImportCommands_[i].addEventListener(
+  for (var i = 0; i < this.autoVisibilityCommands_.length; i++) {
+    this.autoVisibilityCommands_[i].addEventListener(
         'hiddenChange', this.updateVisibility_.bind(this));
   }
   this.updateVisibility_();
@@ -92,7 +92,7 @@ PreviewPanelModel.prototype.updateVisibility_ = function() {
     case PreviewPanelModel.VisibilityType.AUTO:
       newVisible =
           this.selection_.entries.length !== 0 ||
-          this.cloudImportCommands_.some(function(command) {
+          this.autoVisibilityCommands_.some(function(command) {
             return !command.hidden;
           });
       break;

ui/file_manager/file_manager/foreground/js/preview_panel_model_unittest.js

@@ -2,24 +2,22 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-/**
- * Timeout in milliseconds to determine if the event is dispatched or not.
- * If the event is dispached in the timeout, the test regards the event is
- * dispatched, otherwise not. Otherwise it regards the event is not dispatched.
- */
-var TIMEOUT_MS = 3000;
-
 function testPreviewPanelModel(callback) {
   document.querySelector('body').innerHTML =
-      '<command class="cloud-import" hidden></command>';
-  var command = document.querySelector('command.cloud-import');
+      '<command class="auto-visibility" hidden></command>';
+  var command = document.querySelector('command.auto-visibility');
   var model = new PreviewPanelModel(PreviewPanelModel.VisibilityType.AUTO);
 
   var testStep = function(step, changed) {
     var waitPromise = new Promise(function(fulfill) {
       model.addEventListener(
           PreviewPanelModel.EventType.CHANGE, fulfill.bind(null, true));
-      setTimeout(fulfill.bind(null, false), TIMEOUT_MS);
+      // The handler of hiddenChange event in PreviewPanelModel dispatches
+      // PreviewPanelModel.EventType.CHANGE event synchronously. Thus if
+      // the below hiddenChange handler is called ahead of the above change
+      // handler, it means PreviewPanelModel.EventType.CHANGE was not
+      // dispatched.
+      command.addEventListener('hiddenChange', fulfill.bind(null, false));
     });
 
     switch (step) {

ui/file_manager/file_manager/main.html

@@ -217,7 +217,7 @@
                shortcut="U+00BE" hide-shortcut-text><!-- Shortcut: '.' -->
       <!-- The visibility is refered by preview panel.  Set hidden until
            visibility is obtained once. -->
-      <command id="cloud-import" class="cloud-import"
+      <command id="cloud-import" class="auto-visibility"
                i18n-values="label:CLOUD_IMPORT_BUTTON_LABEL" hidden>
 
       <command id="zoom-in" shortcut="U+00BB-Ctrl">