GitLab

If the UpdateBrowserControlsState is sent before the view (and main
frame) are created then it won't go anywhere.

Ensure the disabling of browser controls state occurs after the main
is created by adding a WebContentsObserver.

BUG=1158712

Change-Id: I96dca9b47381291769a6727ad973656559a6701d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2613151Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841055}