This song appears to be about Kurt Cobain. Here's the evidence:
"Resolve" - This could mean coming to a final decision on Cobain's Death, or resolve in musical terms means going from a harsh, disagreeable combination of sounds to a close correspondence of sounds (ie. Nirvana's Distortion to Foo Fighter's Harmonic Sound).
"Swingin' from the chandeliers" - in Nirvana's "Come As You Are" video, Cobain is Swinging from the chandelier.
"I remember watchin' you, once upon a time, Dancing from across the room" - As Nirvana played, all Dave Grohl could do was watch Kurt dance about the stage while he was stuck behind his drums.
"In another life" - for Grohl, so much has happened since Nirvana it seems so long ago.
"Lookin' back to find my way, never seemed so hard" - after Kurt's death, Dave found he had some hard decisions, as Nirvana was no more.
"Yesterday's been laid to rest" - Kurt's been laid to rest."Changing of the guard" - Dave felt he had to look out for Kurt, now he is saying that is someone else's role (God).
"I would never change a thing, even if I could" - Dave wouldn't have it any other way because he would not have gotten the chance to write songs and sing. It could also mean he wouldn't change a thing about when him and Kurt were together.
"All the songs we used to sing, everything was good" - Dave used to do some backing vocals on Nirvana tracks, doubled up with Kurt's voice.
AJ - London, England