Removes ununsed member variable MultibufferDataSource::frame_.

Change-Id: I0f40eb26f3f74cf3effc08aa37dff5caff407e61
Reviewed-on: https://chromium-review.googlesource.com/580671
Commit-Queue: Alok Priyadarshi <alokp@chromium.org>
Reviewed-by: Fredrik Hubinette <hubbe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488767}
4 files changed