Android: Add wnwen@ to chrome/android/features/OWNERS

Makes it easier porting new features over and editing BUILD.gn files.

Bug: None
Change-Id: I2012addc54df4ee62581d7fade7402e9e486b2e9
Reviewed-on: https://chromium-review.googlesource.com/c/1494934
Auto-Submit: Peter Wen <wnwen@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636425}

chrome/android/features/OWNERS

 agrieve@chromium.org
 tiborg@chromium.org
+wnwen@chromium.org