Ensure blob typeface information survives SkGPipe serialization.

When flattening text blobs to the temp buffer, we need to collect
typeface info and ship it across the pipe explicitly.

R=mtklein@google.com, reed@google.com, robertphillips@google.com, bungeman@google.com
BUG=412445

Author: fmalita@chromium.org

Review URL: https://codereview.chromium.org/563783003
5 files changed