Fix: Selection is not correctly used for SuggestionsPopup.

This happens because suggestions are gathered based on the
selection after setting the cursor position to the middle
of the user selected range, which means 0-width selection
at that position. As a result, SuggestionsPopup was not
shown when any suggestion spans don't overlap middle point
of the selection.

Bug: 20709442
Change-Id: I3e1cb570f451b4ab14cf36f7da23dc2bd22f4ac8