[OSX] Revert deferred-window change for FramedBrowserWindow.
The change from defer:YES to defer:NO appears to have caused a perf
regression in startup.warm.blank_page . My best hypothesis is that
Chromium doesn't provide all info at creation time, instead it sets size
and contents and the like piecemeal. With defer:YES, these things
short-circuit operations which need to touch the backing store, while
with defer:NO they actually make changes.
This reverts part of:
https://chromium.googlesource.com/chromium/src/+/
fa89814df86cd44a
BUG=496116
Review URL: https://codereview.chromium.org/
1152943004
Cr-Commit-Position: refs/heads/master@{#333218}