Make the audio codecs' GN targets self-sufficient
Make the audio codecs' GN targets self-sufficient

Also running "gn format" on the file.

R=kwiberg@webrtc.org

Review URL: https://codereview.webrtc.org/1494993002 .

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#10886}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: d048aa0e64cfb4a1633d379736405c060b881554

jchavanton/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,aleonliao/webrtc-trunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,jchavanton/webrtc,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,jchavanton/webrtc,aleonliao/webrtc-trunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,jchavanton/webrtc,jchavanton/webrtc