Preview at WWDC likely in June, followed by September launch.
iOS 8.4 Removes Home Sharing for Music
Apple yesterday updated a Home Sharing support document to note that Home Sharing on iOS devices is only limited to video. Thus far, Home Sharing for music still appears to be available for both Mac and Apple TV. Additionally, while the Music page in iOS' Settings once listed a Home Sharing option prior to iOS 8.4, the option is no longer there in the new Apple Music settings page in iOS 8.4.
As pointed out by AppleInsider, the release notes for iOS 8.4 beta 4 mentioned that Home Sharing and Genius Mixes were "not currently available", offering the possibility that the feature could return in future versions of iOS.
While the possibility of Home Sharing for music returning on iOS devices is there, it's unclear whether Apple would return the option for non-subscribers of Apple Music. The music service includes the ability to sign up for a $14.99-a-month family plan, which allows access for up to 6 people.