Check for text type before setting text span.

The text from the empty text view can be any CharSequence. Need to check
the actual type before trying to cast it to Spannable and setting the
text span.

Change-Id: Ib3ead0a0fe0b797e026c0c259591025fc9c94709
Fix: 34075068
Test: make RunSettingsRoboTests
2 files changed