UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36

Steps to reproduce the problem:
N/A

What is the expected behavior?

What went wrong?
To ensure backwards compatibility with older data, the 'origin' field in proto::CacheStorageIndex should only accept an origin url has a trailing "/".

A test is needed to ensure this.

Did this work before? No 

Chrome version: 61.0.3163.100  Channel: dev
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: Shockwave Flash 27.0 r0