GitLab

gfx::Image object is not threadsafe, we process the image async to
avoid blocking UI thread but causes DCHECK error.  Now we explicity
transfer ownership of the object down to the callback.

BUG=None
TEST=running with DCHECK on and no error triggered after change.

Change-Id: I1b3f678ddd9a411c59328e67de44b4e5db7ae865
Reviewed-on: https://chromium-review.googlesource.com/764373
Commit-Queue: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517128}