Fix OBB tests to stop caring about implementation

The OBB tests were using the OBB API in a way that the documentation
doesn't recommend. Instead of assuming that we already have the
canonical path to an OBB, get the canonical path that is returned in the
observer instead.

Bug: 4371021
Bug: 4364321
Change-Id: Ic4ccd51cc0e173ccd07223508caafc45a9d13e37
1 file changed