GitLab

CWVSyncController needs a way to unobserve signin::IdentityManager
before its associated CWVWebViewConfiguration destroys its
WebViewBrowserState. This avoids a DCHECK in the IdentityManager's
observer list.

Change-Id: I1a0d15bc4bc57a3cf1dd7fbc5a38bdb0adefad0f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2067472Reviewed-by: Hiroshi Ichikawa <ichikawa@chromium.org>
Commit-Queue: John Wu <jzw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743390}