Add magchen@ as an owner of Direct Compoisition in ui/gl

Change-Id: I726e5a34d7ea5d0b3d7455e1047169e72f4047e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2545069Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Maggie Chen <magchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828400}

ui/gl/OWNERS

@@ -8,5 +8,8 @@ per-file *_ozone*=dnicoara@chromium.org
 per-file *_ozone*=spang@chromium.org
 per-file *surface_control*=khushalsagar@chromium.org
 
+# For Windows Direct Composition and Swap Chain
+magchen@chromium.org
+
 # COMPONENT: Internals>GPU>Internals
 # TEAM: graphics-dev@chromium.org