Add pkasting@ for base/time/ and base/callback_list* OWNERS.

Bug: none
Change-Id: I886fafad53efed1be8bd51d9f91f7e04636fe34f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2364700
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799807}

diff --git a/base/OWNERS b/base/OWNERS
index 7555c11f..4ca3417 100644
--- a/base/OWNERS
+++ b/base/OWNERS

@@ -22,7 +22,7 @@
 # For Windows-specific changes:
 per-file *_win*=file://base/win/OWNERS
 
-# For FeatureList API:
+per-file callback_list*=pkasting@chromium.org
 per-file feature_list*=asvitkine@chromium.org
 per-file feature_list*=isherman@chromium.org