Spans should be preserved in TextInfo whenever possible

This is a follow up CL for Ib58ece68dee4c6187d469049fca8c3.

Now SpellCheckerService is expected to store span information
in TextInfo whenever possible so that spell checker service
can use it later.

BUG: 15869548
Change-Id: I481a2efe359de6162ebe095f60506aba3db3d762
1 file changed