commit f11fd346f91a99b706eb4afb0b29dfb25226b77e
author Sylvain Defresne <sdefresne@chromium.org> Wed Jun 01 18:06:06 2022
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jun 01 18:06:06 2022
tree 4e202046d3d06c68b000c6a84f36d1f6e6f3d18a
parent df6de1811357aaeefc85bfc19c6d8ec5a003a18b

[ios] Fix sequence safety issue in ChromeActivityItemThumbnailGenerator

The ChromeActivityItemThumbnailGenerator instance may be deallocated on
a background thread managed by UIKit under certain circumstances. This
is unsafe because WebState is bound to the main UI thread sequence. It
thus crashed when the WebStateObserver was unregistered.

As the WebStateObserver was used to check for the destruction of the
WebState, it is simpler to use base::WeakPtr<web::WebState> which is
safe to destroy (but not access) on a background thread.

Add a unit test that dealloc a ChromeActivityItemThumbnailGenerator on
a background sequence, check that it failed with the old code and pass
with the new implementation.

Move the check for IsOffTheRecord() outside of the object initializer
as it allow to make the tests simpler (there is no need to create a
fake ChromeBrowserState).

(cherry picked from commit 5938e3414233044ac44257571be0f95228adeb72)

Fixed: 1326659
Change-Id: I1210ced4ce7a6e4a281ae095b1a33b84573febeb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3655346
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1005716}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3682467
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/5060@{#461}
Cr-Branched-From: b83393d0f4038aeaf67f970a024d8101df7348d1-refs/heads/main@{#1002911}