[Files app] Convert file_selection.js to es6 classes

Used lebab to convert to ES6 class with the following command:
lebab --replace \
 ui/file_manager/file_manager/foreground/js/file_selection.js \
 --transform class

Manual fixes:
- Fix closure markup to go to constructor() instead of class
definition.
- Fix Mock class to be ES6 class too, since closure doesn't allow
old style classes to extends from ES6 classes.
- Rename MockFileSelectionHandler to FakeSelectionHandler. This fake
lies to closure by saying that it extends FileSelectionHandler to allow
it to be passed as FileSelectionHandler in closure compilation.
- Add addEventListener() method to FakeFileSelectionHandler to fix
tests that use this method.

Bug: 778674
Change-Id: I39fb5ef7d7d8ef9c7fbc2b64244a26b9ebe23584
Reviewed-on: https://chromium-review.googlesource.com/c/1457700Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629911}

ui/file_manager/file_manager/foreground/js/file_selection.js

@@ -4,12 +4,13 @@
 
 /**
  * The current selection object.
+ */
+class FileSelection {
+  /**
    * @param {!Array<number>} indexes
    * @param {!Array<Entry>} entries
- * @constructor
- * @struct
    */
-function FileSelection(indexes, entries) {
+  constructor(indexes, entries) {
     /**
      * @public {!Array<number>}
      * @const
@@ -79,9 +80,9 @@ function FileSelection(indexes, entries) {
       }
       this.totalCount++;
     });
-}
+  }
 
-FileSelection.prototype.computeAdditional = function(metadataModel) {
+  computeAdditional(metadataModel) {
     if (!this.additionalPromise_) {
       this.additionalPromise_ =
           metadataModel
@@ -90,7 +91,8 @@ FileSelection.prototype.computeAdditional = function(metadataModel) {
                   constants.FILE_SELECTION_METADATA_PREFETCH_PROPERTY_NAMES)
               .then(props => {
                 const present = props.filter(p => {
-                // If no availableOffline property, then assume it's available.
+                  // If no availableOffline property, then assume it's
+                  // available.
                   return !('availableOffline' in p) || p.availableOffline;
                 });
                 const hosted = props.filter(p => {
@@ -105,25 +107,26 @@ FileSelection.prototype.computeAdditional = function(metadataModel) {
               });
     }
     return this.additionalPromise_;
-};
+  }
+}
 
 /**
  * This object encapsulates everything related to current selection.
- *
+ */
+class FileSelectionHandler extends cr.EventTarget {
+  /**
    * @param {!DirectoryModel} directoryModel
    * @param {!FileOperationManager} fileOperationManager
    * @param {!ListContainer} listContainer
    * @param {!MetadataModel} metadataModel
    * @param {!VolumeManager} volumeManager
    * @param {!AllowedPaths} allowedPaths
- * @extends {cr.EventTarget}
- * @constructor
    * @struct
    */
-function FileSelectionHandler(
+  constructor(
       directoryModel, fileOperationManager, listContainer, metadataModel,
       volumeManager, allowedPaths) {
-  cr.EventTarget.call(this);
+    super();
 
     /**
      * @private {DirectoryModel}
@@ -176,50 +179,12 @@ function FileSelectionHandler(
     // Register evnets to update file selections.
     directoryModel.addEventListener(
         'directory-changed', this.onFileSelectionChanged.bind(this));
-}
-
-/**
- * @enum {string}
- */
-FileSelectionHandler.EventType = {
-  /**
-   * Dispatched every time when selection is changed.
-   */
-  CHANGE: 'change',
+  }
 
   /**
-   * Dispatched |UPDATE_DELAY| ms after the selecton is changed.
-   * If multiple changes are happened during the term, only one CHANGE_THROTTLED
-   * event is dispatched.
-   */
-  CHANGE_THROTTLED: 'changethrottled'
-};
-
-/**
- * Delay in milliseconds before recalculating the selection in case the
- * selection is changed fast, or there are many items. Used to avoid freezing
- * the UI.
- * @const {number}
- */
-FileSelectionHandler.UPDATE_DELAY = 200;
-
-/**
- * Number of items in the selection which triggers the update delay. Used to
- * let the Material Design animations complete before performing a heavy task
- * which would cause the UI freezing.
- * @const {number}
- */
-FileSelectionHandler.NUMBER_OF_ITEMS_HEAVY_TO_COMPUTE = 100;
-
-/**
- * FileSelectionHandler extends cr.EventTarget.
- */
-FileSelectionHandler.prototype.__proto__ = cr.EventTarget.prototype;
-
-/**
    * Update the UI when the selection model changes.
    */
-FileSelectionHandler.prototype.onFileSelectionChanged = function() {
+  onFileSelectionChanged() {
     const indexes = this.listContainer_.selectionModel.selectedIndexes;
     const entries = indexes.map(index => {
       return /** @type {!Entry} */ (
@@ -240,7 +205,8 @@ FileSelectionHandler.prototype.onFileSelectionChanged = function() {
     const now = Date.now();
 
     if (now > (this.lastFileSelectionTime_ || 0) + updateDelay &&
-      indexes.length < FileSelectionHandler.NUMBER_OF_ITEMS_HEAVY_TO_COMPUTE) {
+        indexes.length <
+            FileSelectionHandler.NUMBER_OF_ITEMS_HEAVY_TO_COMPUTE) {
       // The previous selection change happened a while ago and there is few
       // selected items, so computation is lightweight. Update the UI without
       // delay.
@@ -257,15 +223,15 @@ FileSelectionHandler.prototype.onFileSelectionChanged = function() {
     }, updateDelay);
 
     cr.dispatchSimpleEvent(this, FileSelectionHandler.EventType.CHANGE);
-};
+  }
 
-/**
+  /**
    * Calculates async selection stats and updates secondary UI elements.
    *
    * @param {FileSelection} selection The selection object.
    * @private
    */
-FileSelectionHandler.prototype.updateFileSelectionAsync_ = function(selection) {
+  updateFileSelectionAsync_(selection) {
     if (this.selection !== selection) {
       return;
     }
@@ -279,13 +245,13 @@ FileSelectionHandler.prototype.updateFileSelectionAsync_ = function(selection) {
       cr.dispatchSimpleEvent(
           this, FileSelectionHandler.EventType.CHANGE_THROTTLED);
     });
-};
+  }
 
-/**
+  /**
    * Returns true if all files in the selection files are selectable.
    * @return {boolean}
    */
-FileSelectionHandler.prototype.isAvailable = function() {
+  isAvailable() {
     if (!this.directoryModel_.isOnDrive()) {
       return true;
     }
@@ -293,28 +259,61 @@ FileSelectionHandler.prototype.isAvailable = function() {
     return !(
         this.isOfflineWithUncachedFilesSelected_() ||
         this.isDialogWithHostedFilesSelected_());
-};
-
+  }
 
-/**
- * Returns true if we're offline with any selected files absent from the cache.
+  /**
+   * Returns true if we're offline with any selected files absent from the
+   * cache.
    * @return {boolean}
    * @private
    */
-FileSelectionHandler.prototype.isOfflineWithUncachedFilesSelected_ =
-    function() {
+  isOfflineWithUncachedFilesSelected_() {
     return this.volumeManager_.getDriveConnectionState().type ===
         VolumeManagerCommon.DriveConnectionType.OFFLINE &&
         this.selection.anyFilesNotInCache;
-};
+  }
 
-/**
+  /**
    * Returns true if we're a dialog requiring real files with hosted files
    * selected.
    * @return {boolean}
    * @private
    */
-FileSelectionHandler.prototype.isDialogWithHostedFilesSelected_ = function() {
+  isDialogWithHostedFilesSelected_() {
     return this.allowedPaths_ !== AllowedPaths.ANY_PATH_OR_URL &&
         this.selection.anyFilesHosted;
+  }
+}
+
+/**
+ * @enum {string}
+ */
+FileSelectionHandler.EventType = {
+  /**
+   * Dispatched every time when selection is changed.
+   */
+  CHANGE: 'change',
+
+  /**
+   * Dispatched |UPDATE_DELAY| ms after the selecton is changed.
+   * If multiple changes are happened during the term, only one CHANGE_THROTTLED
+   * event is dispatched.
+   */
+  CHANGE_THROTTLED: 'changethrottled'
 };
+
+/**
+ * Delay in milliseconds before recalculating the selection in case the
+ * selection is changed fast, or there are many items. Used to avoid freezing
+ * the UI.
+ * @const {number}
+ */
+FileSelectionHandler.UPDATE_DELAY = 200;
+
+/**
+ * Number of items in the selection which triggers the update delay. Used to
+ * let the Material Design animations complete before performing a heavy task
+ * which would cause the UI freezing.
+ * @const {number}
+ */
+FileSelectionHandler.NUMBER_OF_ITEMS_HEAVY_TO_COMPUTE = 100;

ui/file_manager/file_manager/foreground/js/task_controller_unittest.js

@@ -108,21 +108,16 @@ function createTaskController(fileSelectionHandler) {
 
 /**
  * Mock FileSelectionHandler.
- * @constructor
  * @extends {FileSelectionHandler}
  */
-function MockFileSelectionHandler() {
-  this.computeAdditionalCallback = function() {};
+class FakeFileSelectionHandler {
+  constructor() {
     this.selection = /** @type {!FileSelection} */ ({});
     this.updateSelection([], []);
-}
-
-MockFileSelectionHandler.prototype = /** @struct */ {
-  __proto__: cr.EventTarget.prototype,
-};
-
-MockFileSelectionHandler.prototype.updateSelection = function(
-    entries, mimeTypes) {
+    this.eventTarget_ = new cr.EventTarget();
+  }
+  computeAdditionalCallback() {}
+  updateSelection(entries, mimeTypes) {
     this.selection = /** @type {!FileSelection} */ ({
       entries: entries,
       mimeTypes: mimeTypes,
@@ -133,7 +128,12 @@ MockFileSelectionHandler.prototype.updateSelection = function(
         });
       },
     });
-};
+  }
+
+  addEventListener(...args) {
+    return this.eventTarget_.addEventListener(...args);
+  }
+}
 
 /**
  * Setup test case fileManagerPrivate.
@@ -165,7 +165,7 @@ function setupFileManagerPrivate() {
  * Tests that executeEntryTask() runs the expected task.
  */
 function testExecuteEntryTask(callback) {
-  var selectionHandler = new MockFileSelectionHandler();
+  var selectionHandler = new FakeFileSelectionHandler();
 
   var fileSystem = new MockFileSystem('volumeId');
   fileSystem.entries['/test.png'] = new MockFileEntry(fileSystem, '/test.png');
@@ -188,7 +188,7 @@ function testExecuteEntryTask(callback) {
  * multiple times when the selected entries are not changed.
  */
 function testGetFileTasksShouldNotBeCalledMultipleTimes(callback) {
-  var selectionHandler = new MockFileSelectionHandler();
+  var selectionHandler = new FakeFileSelectionHandler();
 
   var fileSystem = new MockFileSystem('volumeId');
   selectionHandler.updateSelection(
@@ -225,7 +225,7 @@ function testGetFileTasksShouldNotBeCalledMultipleTimes(callback) {
  * called.
  */
 function testGetFileTasksShouldNotReturnObsoletePromise(callback) {
-  var selectionHandler = new MockFileSelectionHandler();
+  var selectionHandler = new FakeFileSelectionHandler();
 
   var fileSystem = new MockFileSystem('volumeId');
   selectionHandler.updateSelection(
@@ -256,7 +256,7 @@ function testGetFileTasksShouldNotReturnObsoletePromise(callback) {
  * the getFileTasks() promise to reject.
  */
 function testGetFileTasksShouldNotCacheRejectedPromise(callback) {
-  var selectionHandler = new MockFileSelectionHandler();
+  var selectionHandler = new FakeFileSelectionHandler();
 
   var fileSystem = new MockFileSystem('volumeId');
   selectionHandler.updateSelection(