[Android] Update OWNERS information (contextmenu)

https://docs.google.com/document/d/1o77S55v19A4wjfbcs1yMZhc3vs3Yo8s-y6G6JLJ-Jlo

Bug: 1112872
Change-Id: Ifdc654662d32a524aad9cae4822a58c36e194b11
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2363073
Auto-Submit: Fred Mello <fredmello@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799120}

chrome/android/java/src/org/chromium/chrome/browser/contextmenu/OWNERS

+twellington@chromium.org
+
+# COMPONENT: UI>Browser>Mobile>ContextMenu
+# TEAM: chrome-android-app@chromium.org
+# OS: Android

chrome/android/javatests/src/org/chromium/chrome/browser/contextmenu/OWNERS

+file://chrome/android/java/src/org/chromium/chrome/browser/contextmenu/OWNERS

chrome/android/junit/src/org/chromium/chrome/browser/contextmenu/OWNERS

+file://chrome/android/java/src/org/chromium/chrome/browser/contextmenu/OWNERS