Downloads : Update to OWNERS file for java code

Change-Id: I960bd9e85f6e8db1c6a5c11814edf87f77f87c1a
Reviewed-on: https://chromium-review.googlesource.com/1121208Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571715}

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

 dtrainor@chromium.org
-jming@chromium.org
 qinmin@chromium.org
+shaktisahu@chromium.org
+xingliu@chromium.org
 
 per-file DownloadActivity.java=twellington@chromium.org

chrome/android/java/src/org/chromium/chrome/browser/download/ui/OWNERS

 dtrainor@chromium.org
+qinmin@chromium.org
+shaktisahu@chromium.org
 twellington@chromium.org
+xingliu@chromium.org