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Issue 839725 link

Starred by 3 users
Status: Assigned
Owner:
sahel@chromium.org
Cc:
█ sandeepkumars@chromium.org
sahel@chromium.org
bokan@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: Android
Pri: 2
Type: Bug-Regression



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flingScroll() - too fast scroll when call flingScroll()

Reported by sangk...@coupang.com, May 4 2018 
Steps to reproduce the problem:
1. call flingScroll() in android native code for android WebView
2. see how far it scrolls

What is the expected behavior?
Scroll the distance as the previous version (Chrome 65)

What went wrong?
It scrolls approximately 3x far in Chrome 66.

Did this work before? Yes Chrome 65

Does this work in other browsers? N/A

Chrome version: 66.0.3359.139  Channel: stable
OS Version: OS X 10.13.4
Flash Version: 

The issue is when invoke WebView's API flingScroll(vx, vy) with a velocity value, Chrome v66 has a huge difference in scroll distance compare to the old versions, which creates an incompatible behavior with old WebView impls and other scrolling components like scrollView. Reproduced on Galaxy S7 and S8.

For instance, calling flingScroll(0, 6000) leads to ~2000 pixel of vertical scrolling on old versions of Chrome, but it leads to ~5000 pixel scrolling on Chrome v66

Comment 1 by pnangunoori@chromium.org, May 7 2018

Labels: Needs-triage-Mobile

Comment 2 by sandeepkumars@chromium.org, May 7 2018

Cc: sandeepkumars@chromium.org
Labels: Needs-Feedback Triaged-Mobile
@sangkwon: Thanks for the report!!

Could you please help us with a sample file where you're seeing this issue, OS, details of your device and if possible attach a screencast as well for further triaging of the issue?

Thanks!!

Comment 3 by z...@coupang.com, May 8 2018 

Hi @sandeepkumars,
Thanks for your follow-up.

I've created an apk to help demonstrate this issue, please find it attached.(source  here https://github.com/LLLZHEN/chrome.flingscroll.demo)
This app helps to call flingScroll() with a input, and prints out the scroll distance of WebView on the screen.

As you can see the attached screenshots, the results are different between Chrome v65 and v66, run on Samsung Galaxy S7, android OS 7.0:
v65 flingScroll(6000) -> scroll 1942 pixel
v66 flingScroll(6000) -> scroll 13082 pixel

Please help to look into which change cause this different.

Thanks!
app-debug.apk
192 KB Download
chrome_v65_flingscroll.png
247 KB View Download
chrome_v66_flingscroll.png
170 KB View Download

Comment 4 by bokan@chromium.org, May 10 2018

Cc: bokan@chromium.org sahel@chromium.org
Labels: -Needs-Feedback
Sahel, any chance browser side fling may be responsible here? It sounds like we're forgetting to apply the device pixel ratio of the device if I had to guess.

Comment 5 by sahel@chromium.org, May 10 2018

Owner: sahel@chromium.org
Status: Assigned (was: Unconfirmed)
I will check this.
►

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