Add bialpio@ to OWNERS of xr-related directories

Change-Id: I735de5c7f56cad4fec89dd3033ad6748a875ebee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1575360
Commit-Queue: Piotr Bialecki <bialpio@chromium.org>
Auto-Submit: Piotr Bialecki <bialpio@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Reviewed-by: Bill Orr <billorr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652617}

chrome/browser/android/vr/arcore_device/OWNERS

+bialpio@chromium.org
 billorr@chromium.org
 ddorwin@chromium.org
 klausw@chromium.org
-mthiesse@chromium.org
-vollick@chromium.org
 
 # TEAM: xr-dev@chromium.org
 # COMPONENT: Blink>WebXR>AR

device/vr/OWNERS

 bajones@chromium.org
+bialpio@chromium.org
 billorr@chromium.org
-mthiesse@chromium.org
 
 per-file *.mojom=set noparent
 per-file *.mojom=file://ipc/SECURITY_OWNERS

third_party/arcore-android-sdk/OWNERS

+bialpio@chromium.org
 ddorwin@chromium.org
-vollick@chromium.org
 
 # TEAM: xr-dev@chromium.org
 # COMPONENT: Internals>XR>AR

third_party/webxr_test_pages/OWNERS

 bajones@chromium.org
+bialpio@chromium.org
 billorr@chromium.org
 klausw@chromium.org