flags: assign {,ui-show-}composited-layer-borders

Bug: None
Change-Id: I47934cdb696aca8e697f7c461495fb67edf4a894
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1508784
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: ccameron <ccameron@chromium.org>
Auto-Submit: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638699}

chrome/browser/flag-metadata.json

@@ -378,7 +378,7 @@
   },
   {
     "name": "composited-layer-borders",
-    // "owners": [ "your-team" ],
+    "owners": [ "ccameron" ],
     "expiry_milestone": 76
   },
   {
@@ -3042,7 +3042,7 @@
   },
   {
     "name": "ui-show-composited-layer-borders",
-    // "owners": [ "your-team" ],
+    "owners": [ "ccameron" ],
     "expiry_milestone": 76
   },
   {