Add OWNERS file for browser/chromeos/apps/intent_helper.

Add mxcai@ as an OWNER of chrome/browser/chromeos/apps/intent_helper.

Bug: None
Change-Id: Ie837b7e3628fe268431ea7fc0174b8ef5f8ba5bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1738087
Commit-Queue: Maggie Cai <mxcai@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684257}

chrome/browser/chromeos/apps/intent_helper/OWNERS

+mxcai@chromium.org
+
+# COMPONENT: Platform>Apps>Foundation
\ No newline at end of file