Fix memory leak in ChooserContextBase::GetGrantedObjects.

Bug: 854329
Change-Id: Ia163d503a4207859cd41c847c9d5f67e77580fbc
Reviewed-on: https://chromium-review.googlesource.com/c/1456080
Reviewed-by: Balazs Engedy <engedy@chromium.org>
Reviewed-by: Raymes Khoury <raymes@chromium.org>
Commit-Queue: Marek Haranczyk <mharanczyk@opera.com>
Cr-Commit-Position: refs/heads/master@{#629919}
void ChooserContextBase::AddObserver(PermissionObserver* observer) {
  permission_observer_list_.AddObserver(observer);
}

void ChooserContextBase::AddObserver(PermissionObserver* observer) {
  permission_observer_list_.AddObserver(observer);
}
