Use linear metrics flag for linear metrics.

Now that no one is using the linear metrics flag directly, change the
meaning from 'no-hinting and subpixel positioning at an odd size when
measuring and just no-hinting when drawing' to meaning 'use linear
metrics'.

This also changes the font hosts to no longer use subpixel positioning
as a proxy for this value. This fixes outstanding bugs in Chromium about
getting the right metrics for hinted fonts.

Change-Id: I033b3d5ad431eba906a89cc0fefc59cd6702a02c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209174
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Herb Derby <herb@google.com>
10 files changed