ComfortNoise: Calculate used scale factor in Q13
ComfortNoise: Calculate used scale factor in Q13

BUG=chromium:666518

Review-Url: https://codereview.webrtc.org/2519873003
Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#15189}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 0eb19602a3a7bab20f31efe93f9de205106f5b48

Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk