Fix ClearBrowsingDataPreferencesTest on O+

Changes the way that ClearBrowsingDataPreferencesTest disables the
automatic granting of notification permissions to the default search
engine.

Previously, it tried to manually set the permission to blocked,
which didn't work on O+ due to it automatically granting the permission
unconditionally as long as the GrantNotificationsToDSE feature was
enabled, causing a DCHECK to be hit due to attempting to change the
notification channel from allowed to blocked.

Instead, simply disable the feature that causes the DSE to get
notification permissions via the command line.

Also drive-by changes the EmbeddedTestServer usage to use the one
provided by the test rule that's automatically spun up and cleaned up
instead of trying to manage it manually within the test.

Bug: 884413
Change-Id: I23867c3374966a9cca4112d614a4710565717096
Reviewed-on: https://chromium-review.googlesource.com/c/1444755
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Christian Dullweber <dullweber@chromium.org>
Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#627349}
1 file changed