Fix metrics on Windows.

Fix metrics on Windows.

With this change, Skia's metrics are much better in general, and
specifically can be made to match the metrics produced by current
Blink code. This allows Blink to use Skia's metrics.

This change will require a number of rebaselines in Skia, since
previous metrics were quite different. This will require about five
rebaslines in Blink, as the new code may cause GDI's matrix to differ
in the low bits.

Committed: https://code.google.com/p/skia/source/detail?r=10399

[bungeman-skia, 2013-07-27 20:37:59]

Committed patchset #1 manually as r10399 (presubmit successful).