GitLab

Adding completion UUID, to make sure EG tear down waits for completion
from -[SceneController dismissModalDialogsWithCompletion:dismissOmnibox:]

Some flakiness in the tests shows that |drainUntilIdleWithTimeout:| is
not enough to make sure all views are fully dismissed before
|removeAnyOpenMenusAndInfoBars| returns.

Explanation of the flakiness:
The test failure is related to: DCHECK(!self.tabSwitcherIsActive) [1],
during the teardown.
This DCHECK is in |completionWithBVC| completion block. This block is
only used by |dismissModalDialogsWithCompletion:dismissOmnibox:| when
the tab switcher is not opened [2].

So the only way to reproduce this failure, is to open the tab switcher
while the views are being dismissed.

During the tear down, |removeAnyOpenMenusAndInfoBars| calls
|dismissModalDialogsWithCompletion:dismissOmnibox:|, and then
|closeAllTabs| is called, which opens the tab switcher.
This is why I suspect |[ChromeEarlGreyUI waitForToolbarVisible:YES]| is
needed in +[ChromeTestCase removeAnyOpenMenusAndInfoBars].

[1] https://source.chromium.org/chromium/chromium/src/+/master:ios/chrome/browser/ui/main/scene_controller.mm;l=1940
[2] https://source.chromium.org/chromium/chromium/src/+/master:ios/chrome/browser/ui/main/scene_controller.mm;l=1960

Fixed: 1143204, 1146459
Change-Id: I152850dbe5844c96ed64919a3a791f44b94f6be7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2612844
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840965}