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Starred by 3 users

Issue metadata

Status: Assigned
Owner:
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Android
Pri: 3
Type: Bug
Proj-VR
Proj-XR
Proj-XR-VR

Blocked on:
issue 847271



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"Enter VR" button in VR Browser triggers scroll gesture DCHECK

Project Member Reported by klausw@chromium.org, Apr 7 2018

Issue description

Chrome Version: ToT 7a0c954204c16fc4e7ef3298bb037eac28506fde
OS: Android

What steps will reproduce the problem?
(1) Open a WebVR/XR page, enter VR
(2) Use App button to exit to VR Browser
(3) Hit the "Enter VR" button via pointer while moving the pointer and/or finger on the touchpad
(4) goto 2

What is the expected result? enters VR

What happens instead?

In a dcheck_always_on build, this sequence sometimes results in a DCHECK error:

04-06 17:17:15.702 20787 20787 F DEBUG   : signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------
04-06 17:17:15.708 20787 20787 F DEBUG   : Abort message: '[FATAL:render_widget_host_impl.cc(1237)] Check failed: !is_in_gesture_scroll_[gesture_event.SourceDevice()] || FlingCancellationIsDeferred(). 

I'm not sure how to reproduce it consistently. It seems to happen when the pointer and/or my finger on the touchpad was moving as I click.
 
Since this is a DCHECK, it won't reproduce in a release build. I've been using dcheck_always_on=true while testing and ran into this, want to make sure it's not a sign of a more serious logic error.
Cc: sahel@chromium.org
Components: Internals>Input

Comment 3 by sahel@chromium.org, Apr 9 2018

Owner: sahel@chromium.org
Status: Assigned (was: Untriaged)
I will take a look.
Labels: -M-67 M-69
Owner: cjgrant@chromium.org
Reclaiming to do a bit more investigation.
When trying to repro this, I hit a separate crash in our own code.  We need to sort that out first...

signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------
[FATAL:ui_input_manager.cc(191)] Check failed: gesture_list->front()->GetType() == blink::WebInputEvent::kGestureScrollEnd (15 vs. 12)

I induced this simply by clicking on and off content while my thumb was wiggling around on the touchpad.
Owner: acondor@chromium.org
I'll be looking into this.
Blockedon: 847271
Cc: -sahel@chromium.org cjgrant@chromium.org
Owner: sahel@chromium.org
We solved the DCHECK on our side. The issue was that we were overriding a kGestureScrollEnd by a kGestureFlingCancel. So, we were probably sending kGestureScrollBegin when another scrolling was in curse. However, I don't see how our DCHECK was not failing before, given that it has been there for quite some time.

Transfering ownership back to sahel@. Feel free to close if the work on our side is enough to do so.

Comment 9 by samdrazin@chromium.org, Today (16 hours ago)

Labels: -M-69

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