Add davidjm@ to watchlist for tab_ui

Change-Id: Ia1da9ea77ada858a8d8e8b502e993257a2e2fda8
Bug: None
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2092124Reviewed-by: David Maunder <davidjm@chromium.org>
Commit-Queue: Mei Liang <meiliang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747891}

WATCHLISTS

@@ -2719,7 +2719,8 @@
                                  'wychen@chromium.org',
                                  'yusufo@chromium.org',
                                  'gogerald@chromium.org',
-                                 'mattsimmons@chromium.org'],
+                                 'mattsimmons@chromium.org',
+				 'davidjm@chromium.org'],
     'tbmv2_metrics': ['speed-metrics-reviews@chromium.org'],
     'telemetry': ['telemetry-reviews@chromium.org'],
     'test_runner': ['mlamouri+watch-test-runner@chromium.org',