Make compositor input-driven smooth scrolling smoother and snappier.
The animation time is now constant instead of proportional to the delta, which
felt sluggish.
The velocity matching in UpdateTarget now handles direction changes correctly,
and scales the first control point on the y axis instead of rotating it, which
gives a smoother velocity transition.
BUG=575
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
Review URL: https://codereview.chromium.org/1420943004
Cr-Commit-Position: refs/heads/master@{#356291}
5 files changed
