Utilities.trim never returns null.

This fixes a crash loop I was seeing on my device and also
preemptively fixes similar NullPointerExceptions.

Bug: 213931730
Test: Manually verified crash loop stopped with this change.
Change-Id: I8d2fc8475d42ac60b7fdc9219421a8c9733c7b9f
(cherry picked from commit 56be73be)