Add Robbie as owner for WebLayer.

Change-Id: Ib46c3dfbcbd26ec3338d5aace58a670c9eaf33d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2574753
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Auto-Submit: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834333}

weblayer/OWNERS

@@ -5,6 +5,7 @@ darin@chromium.org
 estade@chromium.org
 jam@chromium.org
 nator@chromium.org
+rmcelrath@chromium.org
 sky@chromium.org
 timvolodine@chromium.org
 tobiasjs@chromium.org