Round mSegRectF and mPointRectF coordinates to pixel size.

Check before and after screenshots with "Digital Color Meter" on Mac,
making sure that pixels correspond to the pixels on the phone.

Flag: android.app.api_rich_ongoing
Fix: 384788572
Test: Post ProgressStyle notification described in the bug
Change-Id: Ic5fad5275c56646407afd426ed593213f6cc9378