Improve text rendering and measurement.

1. Fix a bug where baseline of the run was modified while rendering
resulting in crooked text in some cases.

2. Use GlyphVector.getLogicalBounds() for text measurement which is more
accurate than getVisualBounds().

3. This change also optimizes text rendering by not computing the advances
for individual glyphs when not needed.

Change-Id: I66792c4d8f50eaf29afa70bccca1e6c812a3fa28