merge oom_score_adj work

These changes were made in the merge commit itself upstream.

BUG=chromium:199401
TEST=booted

(cherry picked from commit 6de9e65ac37b000dccdc6954260b4d651c43ad9f)
Reviewed-on: https://chromium-review.googlesource.com/2299
Change-Id: I035c9a82490cc2d1bf8e993894cbc2d249bdff90
5 files changed