Revert "Revert "use unique_ptr for stream api""

This reverts commit 7031b247c9fe0cb8fa32129f9bc24fea2043cee2.

Bug: skia:
Change-Id: I24c34bbee703f02994be8e206bcb9c10b5427d84
Reviewed-on: https://skia-review.googlesource.com/47541
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
16 files changed