Adjust distance field glyph and font atlas sizes to maximize storage.

Adjust distance field glyph and font atlas sizes to maximize storage.

Because of high DPI devices, we need more room in the glyph
atlas for the larger glyphs. These settings will allow 4 of
the distance field glyphs to fit in one Plot (increasing
the storage from 32 large glyphs to 128), and still permit
us to handle glyphs up to a 312 point size.

BUG=chromium:458791

Committed: https://skia.googlesource.com/skia/+/d2737ad7dd8f4ea94a74034027014fd3d78923cb

Review URL: https://codereview.chromium.org/986343002