Bug 165474 – Scroll position jumps to the origin when scrolling without momentum at the end of a scroll snapping container

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Wenson Hsieh]

Happens on ToT, after adopting AppKit scroll snapping animations.

There are two ways to reproduce this problem:
1. Go to http://whsieh.github.io/examples/iphone-overflow
2. Scroll to the bottom, so that the last image completely fills the container
3. End the scroll gesture without momentum
 - This will occasionally result in the container's scrollTop jumping to 0.

Another way:
0. Go to any website
1. Navigate to http://whsieh.github.io/examples/iphone-mainframe
2. Scroll left slightly to reveal the previous page but release without momentum so the browser doesn't navigate to the previous page
 - This will result in the mainframe's scrollTop jumping to 0.

[Wenson Hsieh]

<rdar://problem/29534305>

[Wenson Hsieh]

Created attachment 296298 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 296298 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=296298&action=review

> Source/WebCore/page/scrolling/mac/ScrollingMomentumCalculatorMac.mm:57
> +        return Seconds(0);

0_s

[Wenson Hsieh]

Comment on attachment 296298 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=296298&action=review

>> Source/WebCore/page/scrolling/mac/ScrollingMomentumCalculatorMac.mm:57
>> +        return Seconds(0);
> 
> 0_s

Good catch -- fixed!

[Wenson Hsieh]

Created attachment 296409 [details]
Patch for landing

[WebKit Commit Bot]

Comment on attachment 296409 [details]
Patch for landing

Clearing flags on attachment: 296409

Committed r209477: <http://trac.webkit.org/changeset/209477>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.