[directorytree] Center plugin_vm SVG icons in 16px .item-icon box

The icon are currently drawn cut-off in the 16px item-icon box. Assume
they have a 0 0 20 20 viewBox. Add that to their SVG and scale down to
16px x 16px (width x height) to center them in the .item-icon box.

Bug: 1028050, 955920
hange-Id: I8da467fd33d5c526f73772b26480b9dd46ec9bf6
Change-Id: I8da467fd33d5c526f73772b26480b9dd46ec9bf6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1934129Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718573}

ui/file_manager/file_manager/foreground/images/volumes/plugin_vm.svg

-<svg xmlns="http://www.w3.org/2000/svg" fill="rgb(90,90,90)">
-  <path d="M7 12v4H4V4a1 1 0 0 1 1-1h8a3 3 0 0 1 3 3v3a3 3 0 0 1-3 3H7zm0-6v3h5a1 1 0 0 0 1-1V7a1 1 0 0 0-1-1H7z"/>
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 20 20">
+  <path fill="rgb(90,90,90)" transform="translate(0,1)" d="M7 12v4H4V4a1 1 0 0 1 1-1h8a3 3 0 0 1 3 3v3a3 3 0 0 1-3 3H7zm0-6v3h5a1 1 0 0 0 1-1V7a1 1 0 0 0-1-1H7z"/>
 </svg>

ui/file_manager/file_manager/foreground/images/volumes/plugin_vm_active.svg

-<svg xmlns="http://www.w3.org/2000/svg" fill="rgb(51,103,214)">
-  <path d="M7 12v4H4V4a1 1 0 0 1 1-1h8a3 3 0 0 1 3 3v3a3 3 0 0 1-3 3H7zm0-6v3h5a1 1 0 0 0 1-1V7a1 1 0 0 0-1-1H7z"/>
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 20 20">
+  <path fill="rgb(51,103,214)" transform="translate(0,1)" d="M7 12v4H4V4a1 1 0 0 1 1-1h8a3 3 0 0 1 3 3v3a3 3 0 0 1-3 3H7zm0-6v3h5a1 1 0 0 0 1-1V7a1 1 0 0 0-1-1H7z"/>
 </svg>