GitLab

- Changed ClipboardNonBacked::ReadImage to run
ReadImageCallback with empty SKBitmap as a crash
happens when it returns without running the callback.

Bug: 1133717
Test: New unit test added.
Change-Id: I6a7264b8b0d0c56e78852ed1822883cdd9c4efc8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2440656
Commit-Queue: Aya Elsayed <ayaelattar@chromium.org>
Reviewed-by: Darwin Huang <huangdarwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814149}