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- Tab scrubbing: change to use 4-finger gestures.
- Desk switch: change to use 3-finger  gestures.
- Overview selection: change to use 4-finger gestures.

BUG=995911
TEST=Manually, modify existing tests.

Change-Id: I867f3c0033647cc15998e6ef3bce02ac43c2ae7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1764832Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689540}