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Issue 750774 link

Starred by 1 user
Status: Fixed
Owner:
█ aelias@chromium.org
inactive
Closed: Aug 2017
Components:
EstimatedDays: ----
NextAction: ----
OS: All
Pri: 3
Type: Bug-Regression



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Fling with zero velocity while autoscrolling.

Project Member Reported by sahel@chromium.org, Jul 31 2017 
Chrome Version: 62.0.3169.0
OS: Win

What steps will reproduce the problem?
(1)Open any page with a scrollable element.
(2)Autoscroll in one direction and go back to the start point.

What is the expected result?
Successfully return the mouse to the start point and continue autoscrolling.

What happens instead?
It hits the following DCHECK:
legacy_input_router_impl.cc(424)] Check failed: input_event.GetType() != blink::WebInputEvent::kGestureFlingStart || static_cast<const blink::WebGestureEvent&>(input_event) .data.fling_start.velocity_x != 0.0 || static_cast<const blink::WebGestureEvent&>(input_event) .data.fling_start.velocity_y != 0.0.
Project Member

Comment 1 by bugdroid1@chromium.org, Aug 10 2017 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/955a7967ee52ade9fd54724a9f798a2fb7477ab3

commit 955a7967ee52ade9fd54724a9f798a2fb7477ab3
Author: Alexandre Elias <aelias@chromium.org>
Date: Thu Aug 10 01:34:08 2017

Remove zero-fling-velocity DCHECKs.

As of https://codereview.chromium.org/2918053002, zero-velocity flings
are used and expected to work (because using FlingCancel instead would
lose the scroller latching information from the first fling which must
be preserved for middle-click autoscroll).  But I had forgotten to
verify against a DCHECK-enabled build.  This deletes all three DCHECKs.

BUG= 750774 , 727964 

Change-Id: If60f5f7699cf88d87adc642f8bffb95da2db8a3a
Reviewed-on: https://chromium-review.googlesource.com/607213
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Commit-Queue: Alexandre Elias <aelias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#493215}
[modify] https://crrev.com/955a7967ee52ade9fd54724a9f798a2fb7477ab3/content/browser/renderer_host/input/legacy_input_router_impl.cc
[modify] https://crrev.com/955a7967ee52ade9fd54724a9f798a2fb7477ab3/ui/events/blink/input_handler_proxy.cc
[modify] https://crrev.com/955a7967ee52ade9fd54724a9f798a2fb7477ab3/ui/events/gestures/blink/web_gesture_curve_impl.cc

Comment 2 by aelias@chromium.org, Aug 10 2017

Status: Fixed (was: Assigned)
►

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