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If neither feature is enabled, only DragToClose mode should be available

BUG=969815
TEST=Manually, Added tests

Change-Id: Iafaab2ef36a5c1f14bfcec266c3c558145a5f7f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1642147Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665693}