GitLab

Move the widget creation to the constructor, so GetWidget() becomes
trivial and removes the need for member variables to be mutable.
BubbleFrameViewTest.GetBoundsForClientViewWithClose also no longer needs
to call GetWidget() for its side effect.

Change-Id: Ic904c808c37be8f4a61bf9e0bccdbc281ba16c0f
Reviewed-on: https://chromium-review.googlesource.com/1123774Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577243}