Set maximumHeaderTextSize based on line count of TextView

Bug: 33844924

Test: manually verified contact name and phonetic name are
      displayed correctly in multi-window mode when contact
      name is of 1 and 2 lines, and phonetic name is of 0,
      1 and 2 lines.

Change-Id: I2a49c3c6cd3de87cf79eeaa7afc6962056d0d66a