GitLab

Remove BrowserThread and WebContents references

Bug: 803135
Change-Id: I791bbeb0bd3d52c497c7bad7d035aaac7440f588
Reviewed-on: https://chromium-review.googlesource.com/981328
Commit-Queue: Min Qin <qinmin@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546008}