ime: Add shend@ to ui/base/ime/OWNERS.

Planning to do a lot of refactoring in this directory, so adding myself as OWNER
to reduce review load.

Change-Id: I27decd0dcdb1e59f76bacaa4949d88031e661062
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2536510Reviewed-by: Keith Lee <keithlee@chromium.org>
Commit-Queue: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827652}

ui/base/ime/OWNERS

@@ -2,6 +2,7 @@
 shuchen@chromium.org
 yhanada@chromium.org
 keithlee@chromium.org
+shend@chromium.org
 
 # backup reviewers.
 yukishiino@chromium.org