Add entry icons on file list

Add iconName property on VolumeEntry and on crostini FakeItem.

Change FileType.getIcon to prefer iconName property if available.

Change CSS to add icon to file-type-icon which is used on file list and
file grid.

The changes above fix crostini (a FakeEntry), downloads and android
(VolumeEntry) to be displayed with proper icons on RHS.

Change directory tree (LHS) icon for shortcut, from "drive" to a new
dedicated icon for shortcuts.

Bug: 846587
Cq-Include-Trybots: luci.chromium.try:closure_compilation
Change-Id: I44e08f9f6d711c45a4e698acbb203e9cb3a87d9d
Reviewed-on: https://chromium-review.googlesource.com/1132258
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575524}
10 files changed