Chrome Version: 61.0.3159.5/dev
OS: MacOS, Retina screen

What steps will reproduce the problem?
(1) Visit http://output.jsbin.com/lefifu/quiet
(2) Place the cursor near the left side of the screen
(3) Use the touchpad to two-finger scroll the page down slowly.

What is the expected result?
Smooth scrolling

What happens instead?
Scrolling stops as soon as the cursor is over a scrollbar

Regression range:
https://chromium.googlesource.com/chromium/src/+log/3b3488538d7cb7ba21ee3766b7a4454df7f5c39a..09fba90138a1c3197d0568fec12ceb75217aedf3

I think this is a regression from:
GSB uses delta_hints to calculate scrolling chain.
https://chromium.googlesource.com/chromium/src/+/60b41cdfe22237cb667050017349375ca9272ccf
 

Chrome Version: 61.0.3159.5/dev
OS: MacOS, Retina screen

What steps will reproduce the problem?
(1) Visit http://output.jsbin.com/lefifu/quiet
(2) Place the cursor near the left side of the screen
(3) Use the touchpad to two-finger scroll the page down slowly.

This requires that "Show scroll bars: Always" is set in MacOS Settings > General, or should occur if a mouse is plugged in.

What is the expected result?
Smooth scrolling

What happens instead?
Scrolling stops as soon as the cursor is over a scrollbar

Regression range:
https://chromium.googlesource.com/chromium/src/+log/3b3488538d7cb7ba21ee3766b7a4454df7f5c39a..09fba90138a1c3197d0568fec12ceb75217aedf3

I think this is a regression from:
GSB uses delta_hints to calculate scrolling chain.
https://chromium.googlesource.com/chromium/src/+/60b41cdfe22237cb667050017349375ca9272ccf