Change default selection in getDisplayMedia to cancel for Mac

To prevent permissions being accepted accidentally, permission prompts should
not be accepted as the default action. This CL changes default selection to
cancel button to reflect that. Earlier CL affected Views, but Mac still uses
its own controller. This CL addresses that specifically.

Bug: 326740, 919456
Change-Id: I0ed7d9c61b3795af6b1ff91f801548d4b7bc1ed3
Reviewed-on: https://chromium-review.googlesource.com/c/1403394
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Emircan Uysaler <emircan@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#621237}(cherry picked from commit 69161eec8ef8e87cf1d196c3b4d6c8eb7869daf9)
Reviewed-on: https://chromium-review.googlesource.com/c/1407033
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#640}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}
2 files changed