Move PWGRasterConverter off the FILE thread.

BUG=689520

Change-Id: I7f2c33cd196e51cf1952fc678f3076d8f2ff02ce
Reviewed-on: https://chromium-review.googlesource.com/590811
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490549}
1 file changed