Use in-class initializers for base::WeakPtrFactory in ui/.

Generated by: https://chromium-review.googlesource.com/c/chromium/src/+/1689216

Bug: 981415
Change-Id: I24b2eb71962f3fe9b2a88580d17ec53372aaaac5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1700362
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#677326}
47 files changed