add SK_SUPPORT_LEGACY_FONTMETRICS_IN_PAINT flag to stage skia api change

Needs this to roll in first
https://skia-review.googlesource.com/c/skia/+/177063

Change-Id: I6ed43335c93e516f7a2f1fb7efc4756206e83bcc
Reviewed-on: https://chromium-review.googlesource.com/c/1374166
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Cr-Commit-Position: refs/heads/master@{#616308}
1 file changed