Remove old or irrelevant smcgruer@ owned TODOs

Bug: 746963
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I60bcffb65161c16521afc22b3aa1ed3d2bfe346d
Reviewed-on: https://chromium-review.googlesource.com/579528


Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488323}