Label logUnits after LatinImeOnEndBatchInput

Previously only a commitText would cause a LogUnit to be
labeled with the word that the data generates.  In the case
of gestured text, this information is available when
LatinIME#onEndBatchInput is called. Labeling the LogUnit
at this time means that the Log will have labeled words even
if stop() is called before commit.

Change-Id: Idb2f99a9c159a1b1aa00448a2ecddeca6c351c3e