Choose smaller or shorter language name for space bar

To fit a language name to the space bar or the language switcher, this
change chooses smaller text size or shorter language name
appropriately.

This change also tunes the vertical position of a language name in the
space bar by parameter SPACEBAR_LANGUAGE_BASELINE.

Bug: 3004640
Bug: 3001021

Change-Id: Idb3adcb6fac1a23836510912d35312fa11b4f259