Use vector icons for file launcher chips

1. Create a white circle background vector icon for launcher chip.
2. Use vector icon for file launcher chips instead of pngs.
3. Remove resources that are no longer required.

Bug: 1067326
Change-Id: I1a18e7c6c8458f84f50930ce47ac87dfcd94e1c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2354373
Commit-Queue: Thanh Nguyen <thanhdng@chromium.org>
Reviewed-by: Evan Stade <estade@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799464}