I am using a Nexus 5 on 4.4.4 and now that I have the Google Now anywhere functionality I can already skip tracks while playing music without any third party apps. This even works while music is playing. I have not tried to pause or resume music. It does bork sometimes either not recognizing my voice or changing to the new track or artist but not playing. As was previously reported here I believe telling Google Now to turn off WiFi is recognized but all it does is take you to that settings page.
i have read something about ：， in this case have catch this interruption notification in code, also can detect the call end status and restart the music , but have no sounds at all
David Wooten Resume Video Music
To be clear, this function of Google Now appears to work with any app that controls your audio and is not explicitly for Play Music. If, for example, the last thing you were listening to was a podcast on Pocket Casts then that's what will start playing with the "resume music" command.