Revert to Immersive Fullscreen on OSX for a special case

If the user is using multiple monitors and turned off "Separate Space
in Each Display", use Immersive Fullscreen so that the other monitors
won't blank out.

BUG=582944,580843

Review URL: https://codereview.chromium.org/1725643002

TBR=avi@chromium.org
Cr-Commit-Position: refs/heads/master@{#377116}
(cherry picked from commit d310f829e7f38f725a5b695ea701a3ffa3b3cf89)

Review URL: https://codereview.chromium.org/1732173004 .

Cr-Commit-Position: refs/branch-heads/2623@{#511}
Cr-Branched-From: 92d77538a86529ca35f9220bd3cd512cbea1f086-refs/heads/master@{#369907}
1 file changed