SkTextBlob GPipe serialization.

Instead of relying on unrolling blobs in SkCanvas, serialize when
passing through a GPipe.

This is a prerequisite for pushing the blob draw op to the device.

R=mtklein@google.com, reed@google.com, robertphillips@google.com

Author: fmalita@chromium.org

Review URL: https://codereview.chromium.org/511783005
3 files changed