Making this a little more specific to the toolbar issue.

The error started when EG was updated, failing consistently.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b3fe115b5f89f0ef92ae9b544db8294ebb5411e4

commit b3fe115b5f89f0ef92ae9b544db8294ebb5411e4
Author: gambard <gambard@chromium.org>
Date: Fri Jan 27 14:15:04 2017

Add a timeout on the EG DrainUntilIdle

This CL adds a timeout of the cleanup functions of the ChromeTestCase.
The cleanup functions wait for the UI thread and waits for both the UI
and idling resources to idle.
Without a timeout, this function hangs the application forever.

BUG= 686069 

Review-Url: https://codereview.chromium.org/2652343005
Cr-Commit-Position: refs/heads/master@{#446663}

[modify] https://crrev.com/b3fe115b5f89f0ef92ae9b544db8294ebb5411e4/ios/chrome/test/earl_grey/chrome_test_case.mm

It is also happening on iPhone on simulator: https://uberchromegw.corp.google.com/i/internal.bling.main/builders/iphone9-simulator/builds/9842
And on iPad simulator:
https://uberchromegw.corp.google.com/i/internal.bling.main/builders/ipad9-simulator/builds/9596
But it is less frequent.

I have never seen it on iOS 10.x

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/29215937d2b774363840defec3d752ffed112655

commit 29215937d2b774363840defec3d752ffed112655
Author: rohitrao <rohitrao@chromium.org>
Date: Fri Jan 27 16:59:05 2017

[ios] Disables ToolbarTestCase.testCopyPasteURL on iOS 9.

BUG= 686069 

Review-Url: https://codereview.chromium.org/2662583002
Cr-Commit-Position: refs/heads/master@{#446692}

[modify] https://crrev.com/29215937d2b774363840defec3d752ffed112655/ios/chrome/browser/ui/toolbar/toolbar_egtest.mm

This looks very similar to the fix we had to do to unblock the EarlGrey roll for us:
https://github.com/google/EarlGrey/pull/400

With that problem, long pressing in a WKWebView would hang with the app state tracker never becoming idle, similar to this case. With this bug, I suspect the problem isn't limited to WKWebView.

I tried removing the call to _clearTouches in GREYTouchInjector.m and it made testCopyPasteURL pass every run (~8 runs). Leaving _clearTouches in, it failed almost every time. My local testing was done on a 32-bit iPad Mini, running iOS 9.3.

I don't think it's a solution to remove _clearTouches from EarlGrey. They said not having it caused memory leaks in tests. Perhaps we can modify the WKWebView workaround for this. Or if this is unrelated to WKWebView we should be able to write an EG test case that exposes the issue.

Okay, I debugged a bit, and disabling synchronization when long pressing doesn't fix it 100% of the time.

I looked, and EG doesn't have any context menu test cases. I'm going to see if I can repro there, and then see about a fix in the framework...

I repro'd something similar in the EG sample app and filed an issue there:
https://github.com/google/EarlGrey/issues/422

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ff6d2f32f1e7c132f9167ccaa55663ffea581dc0

commit ff6d2f32f1e7c132f9167ccaa55663ffea581dc0
Author: Mike Baxley <baxley@chromium.org>
Date: Wed Nov 22 15:29:44 2017

Remove code disabling testCopyPasteURL on iOS 9.

We no longer support iOS 9, so the test no longer has to filter
this case.

Bug:  686069 
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ib2f55b54fc7ad4d1843971044683262a912e9f51
Reviewed-on: https://chromium-review.googlesource.com/783552
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Mike Baxley <baxley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518638}
[modify] https://crrev.com/ff6d2f32f1e7c132f9167ccaa55663ffea581dc0/ios/chrome/browser/ui/toolbar/toolbar_egtest.mm

I believe this bug was fixed in an EarlGrey touch injection fix we recently rolled ( crbug.com/685570 ). But we don't support iOS 9, so closing this as WontFix.