Update owners file for input method

Change-Id: If5571ec114544bd69bef816b53e138ae6b5709b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1900509Reviewed-by: Darren Shen <shend@chromium.org>
Reviewed-by: David Vallet <dvallet@chromium.org>
Reviewed-by: Shu Chen <shuchen@chromium.org>
Commit-Queue: David Vallet <dvallet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714653}

chrome/browser/resources/chromeos/input_method/OWNERS

+shend@chromium.org
+dvallet@chromium.org
 shuchen@chromium.org
 fengyuan@chromium.org
 wuyingbing@chromium.org