Change tests that fail with wheel scroll latching and async wheel on.

This cl fixes failing content_browsertests and content_unittests when
the wheel scroll latching and async wheel events are enabled.

This also changes synthetic_smooth_move_gesture to prevent smoothScrollBy
from sending synthetic wheel events with zero deltas and
phase!=phaseEnded.

TBR: [email protected]
Bug: 526463
Change-Id: Ib28f9dcbe11520d7e8a46fe05cb2d2eb92d6ba80
Reviewed-on: https://chromium-review.googlesource.com/602477
Commit-Queue: Sahel Sharifymoghaddam <[email protected]>
Reviewed-by: Erik Chen <[email protected]>
Reviewed-by: James MacLean <[email protected]>
Reviewed-by: Nasko Oskov <[email protected]>
Reviewed-by: Timothy Dresser <[email protected]>
Cr-Commit-Position: refs/heads/master@{#495173}
12 files changed