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Issue 778566 link

Starred by 3 users

Issue metadata

Status: Assigned
Owner:
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: 2
Type: Bug-Regression



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Regression:'show page contents' text is seen misplaced on scrolling the page of www.quirksmode.org/html5/tests/video.html

Project Member Reported by rkalavakuntla@chromium.org, Oct 26 2017

Issue description

Chrome Version:63.0.3239.20/10032.17.0 dev-channel Candy,Daisy,Reks
OS:Chrome OS

What steps will reproduce the problem?
(1)Sign into user -> Launch Chrome and navigate to https://www.quirksmode.org/html5/tests/video.html
(2)Click on 'show page contents' text present on top-right corner ->Scroll the page and Observe the misplacement of that text(kindly refer video)

Actual:'show page contents'text is seen misplaced when page is scrolled
Expected: Instead, the text doesn't get misplaced on scrolling the page.

This is a Regression issue as same is working fine in 61.0.3163.120/9765.81.0 dev channel Daisy

Note:
1. Issue is not seen in Windows, Linux OS
2. Issue is also seen in latest M-64




 
actualmisplace.webm
3.2 MB View Download
expected.webm
837 KB View Download
++Correction:
Expected: Text scrolls up & down and comes back to its default position where the text is present 
Actual: Instead of coming to its default position, it moves upwards on the blue header and its contents too..

Comment 2 by zork@chromium.org, Oct 27 2017

Components: -UI Blink
Reproduces with  --enable-prefer-compositing-to-lcd-text on Linux.
Scratch comment 3. It repros with devtools mobile emulation on. Bisecting now.

Components: -Blink Blink>Layout
Labels: -M-63 M-62
Owner: skobes@chromium.org
Status: Assigned (was: Untriaged)
Bisect:

https://chromium.googlesource.com/chromium/src/+log/68374d6fc868984795f7ecb5457f7e4009d16de8..f470dd6dfd2e88e40e344e5bd914c90c999ddbe4

Suspecting a655402.
Owner: chrishtr@chromium.org
This is not r489392, but rather r489395.  Back to chrishtr.
Labels: -ReleaseBlock-Stable
Not blocking initial stable on this but willing to merge for stable refresh if safe CL is available 
Components: -Blink>Layout Blink>Scroll
Labels: -Pri-1 Pri-2
Owner: ----
Status: Untriaged (was: Assigned)
I don't think my CL could have introduced this regression. I think there is
either a site bug related to this particular setup of composited scrolling, or
a bug in the input system in which it doesn't pass enough scroll events or
with the right parameters.

Does the input system guarantee eventual consistency of composited scrolling?
Meaning: even though the scroll events come async to the actual scroll, they
add up to the total scroll offset when quiescent.

Untriaging and sending to the scroll component.
Cc: bokan@chromium.org dtapu...@chromium.org
Cc: flackr@chromium.org
Components: Internals>Compositing>Scroll
Seems that onScroll isn't invoked sometimes.

flackr@ do you know of any bugs that cause a commit to happen on the cc side and the main thread isn't told about it?

Comment 11 by bokan@chromium.org, Nov 16 2017

flackr@, ping.

Comment 12 by fsamuel@google.com, Nov 17 2017

Owner: flackr@chromium.org
Status: Assigned (was: Untriaged)
flackr@ for triage.
I'm aware of the scroll offset synced back to main being off by one (issue 681951) but that shouldn't cause this as far as I can tell. I will investigate.
Labels: Hotlist-Polish
This still reproduces on 69.0.3497.92 (Official Build) (64-bit) Linux, using devtools mobile emulation (Responsive, 1200x800, using touch-based scrolling.)

Comment 16 by flackr@chromium.org, Yesterday (47 hours ago)

Owner: chrishtr@chromium.org
Looking at this in dev tools, this appears to be missing an invalidation / layer property update. Observing the #header element the top value seems to be updating correctly on every scroll, but the layer doesn't always visually update its position. Hovering over the element in the devtools elements panel triggers a repaint which fixes the position.

Chris, can you look into the invalidation issue.

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