Friendly ping to look into this issue and to provide further update on this issue as it has been marked as a stable blocker.

Thanks!

Friendly ping to look into this issue and to provide further update on this issue as it has been marked as a stable blocker.

Thanks!

miu@, should this be considered a RBS?

I don't know. vmpstr@ was the one that added the DCHECK which caused regular crashes on my local "DCHECK is on" build. Perhaps they could shed some light on all of this?

ref: https://chromium.googlesource.com/chromium/src/+blame/HEAD/third_party/blink/renderer/core/layout/intersection_geometry.cc#162

The question here is: If the conditions that trigger the DCHECK occur in "DCHECK is off" builds (e.g., official release builds), will that lead to undefined/crashy behavior? I couldn't tell, which is why I've been treating this like I would any other crash report, which are usually RBS.

Friendly ping! Could you please provide any update on this issue as it has been marked as a stable blocker.

Thank You!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/020d4423e05c0421b8081fa2ffee9ec8f3ec846d

commit 020d4423e05c0421b8081fa2ffee9ec8f3ec846d
Author: Stefan Zager <szager@chromium.org>
Date: Thu Jan 10 03:42:41 2019

Use IntersectionObserver in MediaCustomControlsFullscreenDetector

It's never safe to use IntersectionGeometry directly from a timer.
Change implementation to use an IntersectionObserver, which always runs
at the right time. This works because whenever observer->observe() is
called, it will generate an initial notification at the next
opportunity, whether the target is initially intersecting or not.

BUG:  916850 
Change-Id: I972ae8defb1c5a3bdcb8cbd52633ec28167c0f8e
Reviewed-on: https://chromium-review.googlesource.com/c/1399452
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Commit-Queue: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621440}
[modify] https://crrev.com/020d4423e05c0421b8081fa2ffee9ec8f3ec846d/third_party/blink/renderer/core/html/media/media_custom_controls_fullscreen_detector.cc
[modify] https://crrev.com/020d4423e05c0421b8081fa2ffee9ec8f3ec846d/third_party/blink/renderer/core/html/media/media_custom_controls_fullscreen_detector.h
[modify] https://crrev.com/020d4423e05c0421b8081fa2ffee9ec8f3ec846d/third_party/blink/renderer/core/html/media/media_custom_controls_fullscreen_detector_test.cc
[modify] https://crrev.com/020d4423e05c0421b8081fa2ffee9ec8f3ec846d/third_party/blink/renderer/core/intersection_observer/intersection_observation.cc
[modify] https://crrev.com/020d4423e05c0421b8081fa2ffee9ec8f3ec846d/third_party/blink/renderer/core/intersection_observer/intersection_observer.cc
[modify] https://crrev.com/020d4423e05c0421b8081fa2ffee9ec8f3ec846d/third_party/blink/renderer/core/intersection_observer/intersection_observer.h
[modify] https://crrev.com/020d4423e05c0421b8081fa2ffee9ec8f3ec846d/third_party/blink/renderer/core/intersection_observer/intersection_observer_test.cc

[bulk update] Just a heads up, M72 stable is about 2 weeks away. This issue is marked as RB-Stable. Please take a look. 

miu@/ why is this RB-Stable?

[Auto-generated comment by a script] We noticed that this issue is targeted for M-72; it appears the fix may have landed after branch point, meaning a merge might be required. The owner of this bug should confirm if a merge is required here. If so, add Merge-Request-72 label and indicate which commits/CLs are to be merged. Otherwise, remove Merge-TBD label. Thanks.

If this is not a frequent crasher, I would prefer not to merge.

Actually, this is a DCHECK, right? So there are probably some crashes in official builds, but I'm guessing the number is pretty low.