Reland "mac: Implement custom AppKit Enter Fullscreen transition."
The original CL was reverted because it introduced a static initializer. This
CL fixes that.
> AppKit's default Fullscreen transition cross-fades between two static images: a
> snapshot of the window before the transition began, and a snapshot of the
> window resized to the full size of the screen. This has the problem that
> frequently, when AppKit takes the snapshot of the final state of the window,
> the web contents view has not yet drawn any content in the new size. The
> animation itself looks weird, and then there's a flash when the animation
> finishes where the snapshot of the old web content is replaced by the new web
> content.
>
> This custom fullscreen transition is very similar, except instead of taking a
> snapshot of the window in its final state, the transition uses a live version
> of the window in its final state. See the associated bug for more details about
> the implementation.
>
> BUG=414527
> Committed: https://crrev.com/
a48cbbba0075b7a7c135605ab576bad2cfa5a1b3
> Cr-Commit-Position: refs/heads/master@{#311717}
BUG=414527
TBR=mark@chromium.org, andresantoso@chromium.org
Review URL: https://codereview.chromium.org/
856573003
Cr-Commit-Position: refs/heads/master@{#312234}