GitLab

When an app/extension places a ZoomController in manual mode, it is
reasonable to expect that navigating the main frame should reset that
mode, since the app/extension will be reloaded in the process.

The root cause of this bug was the sending of a ZoomChangeEvent that
contained stale information (the old, manually managed, zoom level),
which in turn caused the zoom bubble to be displayed.

BUG=450909

Review URL: https://codereview.chromium.org/884063004

Cr-Commit-Position: refs/heads/master@{#313576}