[Reland attempt #2] Refactor DirectoryTree

Fix flakiness by adding call to this.expanded=true in EntryListItem.

Change updateSubDirectories:
- use arrow function and const;
- change error callback calling style to match the same style used by
success callback (without if).
- change check from isFakeEntry to check for presence of the method
that's used "createReader".

Change the sorting to be an method, so it can be customized per
sub-class, later it will be used to sort My files to show Linux and Play
files at the bottom.

Fix unittest that started failing because it metadataModel was null.

No changes in behaviour for users, the small change in behaviour is
EntryListItem.updateSubDirectories now reads its children using FS API
which isn't synchronous.

CrOS FilesApp UI Tests: ensure downloads selected and refreshed in setup

TBR: joelhockey@chromium.org
Bug: 899664
Change-Id: I8a93616f74cf3bf2b99851dc2452249e1353d85e
Reviewed-on: https://chromium-review.googlesource.com/c/1306963Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604069}

ui/file_manager/file_manager/foreground/js/directory_model.js

@@ -972,6 +972,8 @@ DirectoryModel.prototype.changeDirectoryEntry = function(
   if (dirEntry instanceof VolumeEntry)
     dirEntry = assert(dirEntry.rootEntry);
 
+  // TODO(lucmult): Remove this log once flakiness is fixed.
+  console.log('changeDirectoryEntry: ',  dirEntry.name);
   // Increment the sequence value.
   this.changeDirectorySequence_++;
   this.clearSearch_();

ui/file_manager/file_manager/foreground/js/ui/directory_tree.js

@@ -482,6 +482,17 @@ DirectoryItem.prototype.handleClick = function(e) {
   }
 };
 
+/**
+ * Default sorting for DirectoryItem sub-dirrectories.
+ * @param {!Array<!Entry>} entries Entries to be sorted.
+ * @returns {!Array<!Entry>}
+ */
+DirectoryItem.prototype.sortEntries = function(entries) {
+  entries.sort(util.compareName);
+  const filter = this.fileFilter_.filter.bind(this.fileFilter_);
+  return entries.filter(filter);
+};
+
 /**
  * Retrieves the latest subdirectories and update them on the tree.
  * @param {boolean} recursive True if the update is recursively.
@@ -490,17 +501,11 @@ DirectoryItem.prototype.handleClick = function(e) {
  */
 DirectoryItem.prototype.updateSubDirectories = function(
     recursive, opt_successCallback, opt_errorCallback) {
-  if (!this.entry || util.isFakeEntry(this.entry)) {
-    if (opt_errorCallback)
-      opt_errorCallback();
+  if (!this.entry || this.entry.createReader === undefined) {
+    opt_errorCallback && opt_errorCallback();
     return;
   }
 
-  const sortEntries = (fileFilter, entries) => {
-    entries.sort(util.compareName);
-    return entries.filter(fileFilter.filter.bind(fileFilter));
-  };
-
   const onSuccess = (entries) => {
     this.entries_ = entries;
     this.updateSubElementsFromList(recursive);
@@ -512,7 +517,7 @@ DirectoryItem.prototype.updateSubDirectories = function(
   const readEntry = () => {
     reader.readEntries((results) => {
       if (!results.length) {
-        onSuccess(sortEntries(this.fileFilter_, entries));
+        onSuccess(this.sortEntries(entries));
         return;
       }
 
@@ -743,26 +748,46 @@ EntryListItem.prototype = {
  */
 EntryListItem.prototype.updateSubDirectories = function(
     recursive, opt_successCallback, opt_errorCallback) {
-  if (!this.entry) {
+  if (!this.entry || this.entry.createReader === undefined) {
     opt_errorCallback && opt_errorCallback();
     return;
   }
   this.entries_ = [];
-  if (this.entry && this.entry.children) {
-    for (let childEntry of this.entry.children) {
-      if (childEntry instanceof VolumeEntry) {
-        // For VolumeEntry we want to display its root.
-        this.entries_.push(childEntry.rootEntry);
-      } else {
-        this.entries_.push(childEntry);
+
+  const onSuccess = (entries) => {
+    this.entries_ = entries;
+    this.updateSubElementsFromList(recursive);
+    if (this.entries_.length > 0)
+      this.expanded = true;
+    opt_successCallback && opt_successCallback();
+    // TODO(lucmult): Remove this log once flakiness is fixed.
+    console.log('EntryListItem children loaded.');
+  };
+
+  const reader = this.entry.createReader();
+  const entries = [];
+  const readEntry = () => {
+    reader.readEntries((results) => {
+      if (!results.length) {
+        onSuccess(this.sortEntries(entries));
+        return;
       }
-    }
-  }
-  if (this.entries_.length > 0) {
-    this.expanded = true;
-  }
-  this.updateSubElementsFromList(recursive);
-  opt_successCallback && opt_successCallback();
+
+      for (let i = 0; i < results.length; i++) {
+        const entry = results[i];
+        if (entry.isDirectory) {
+          // For VolumeEntry we want to display its root.
+          if (entry instanceof VolumeEntry) {
+            entries.push(entry.rootEntry);
+          } else {
+            entries.push(entry);
+          }
+        }
+      }
+      readEntry();
+    });
+  };
+  readEntry();
 };
 
 ////////////////////////////////////////////////////////////////////////////////

ui/file_manager/file_manager/foreground/js/ui/directory_tree_unittest.js

@@ -501,8 +501,9 @@ function testUpdateSubElementsFromListSections() {
   assertEquals(NavigationSection.MY_FILES, myFilesItem.section);
   assertEquals(NavigationSection.CLOUD, driveItem.section);
 
+  const metadataModel = mockMetadataModel();
   DirectoryTree.decorate(directoryTree, directoryModel, volumeManager,
-      null, fileOperationManager, true);
+      metadataModel, fileOperationManager, true);
   directoryTree.dataModel = treeModel;
   directoryTree.updateSubElementsFromList(false);
 
@@ -958,9 +959,10 @@ function testInsideMyDriveAndInsideDrive(callback) {
       .webkitResolveLocalFileSystemURLEntries['filesystem:downloads/folder1'] =
       new MockDirectoryEntry(downloadsFileSystem, '/folder1');
 
+  const metadataModel = mockMetadataModel();
   DirectoryTree.decorate(
-      directoryTree, directoryModel, volumeManager, null, fileOperationManager,
-      true);
+      directoryTree, directoryModel, volumeManager, metadataModel,
+      fileOperationManager, true);
   directoryTree.dataModel = new MockNavigationListModel(volumeManager);
   directoryTree.redraw(true);