CrOS FilesApp: Allow share drive computer volumes with crostini

We currently have COMPUTERS_GRAND_ROOT as a sharable volume, but
once you drill into a specific Drive Computer, the volume is COMPUTER.

Bug: 878324
Change-Id: I25a4bf377200b37c9e5914ad558a3596484f4915
Reviewed-on: https://chromium-review.googlesource.com/c/1300354Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603004}

ui/file_manager/file_manager/foreground/js/crostini.js

@@ -17,6 +17,7 @@ Crostini.IS_CROSTINI_FILES_ENABLED = false;
  */
 Crostini.VALID_ROOT_TYPES_FOR_SHARE = new Map([
   [VolumeManagerCommon.RootType.COMPUTERS_GRAND_ROOT, 'DriveComputers'],
+  [VolumeManagerCommon.RootType.COMPUTER, 'DriveComputers'],
   [VolumeManagerCommon.RootType.DOWNLOADS, 'Downloads'],
   [VolumeManagerCommon.RootType.DRIVE, 'MyDrive'],
   [VolumeManagerCommon.RootType.TEAM_DRIVE, 'TeamDrive'],

ui/file_manager/file_manager/foreground/js/crostini_unittest.js

@@ -64,9 +64,7 @@ function testCanSharePath() {
   assertFalse(Crostini.canSharePath(fooFolder, true, volumeManager));
   assertFalse(Crostini.canSharePath(fooFolder, false, volumeManager));
 
-  for (type of
-           ['downloads', 'drive', 'team_drive', 'computers_grand_root',
-            'removable']) {
+  for (type in Crostini.VALID_ROOT_TYPES_FOR_SHARE) {
     volumeManagerRootType = type;
     assertFalse(Crostini.canSharePath(root, true, volumeManager));
     assertFalse(Crostini.canSharePath(root, false, volumeManager));