GitLab

Currently, the scrollbar layer animation is triggered at the end of every scroll
gesture. However, as not every scroll gesture actually scrolls a layer, this may
trigger extraneous animations, e.g., when the user overscrolls, or presses and
lifts their finger without scrolling.  Only trigger the scrollbar animation at
the end of a scroll gesture if the gesture caused the layer to scroll.

BUG=285771

Review URL: https://chromiumcodereview.appspot.com/23978008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221801 0039d316-1c4b-4281-b951-d872f2087c98