Remove dependency on AppAudioManager

Implement speakerphone toggle directly. Previously we were using
AppAudioManager for several things, but this is that last lingering bit.
Much of the AppAudioManager code is based on RedPhone calling, so by
removing the dependency we pave the way to throw that code away.

// FREEBIE

Signal/src/call/CallAudioService.swift

@@ -7,7 +7,6 @@ import Foundation
 @objc class CallAudioService: NSObject {
     private let TAG = "[CallAudioService]"
     private var vibrateTimer: Timer?
-    private let audioManager = AppAudioManager.sharedInstance()
     private let soundPlayer = JSQSystemSoundPlayer.shared()!
 
     enum SoundFilenames: String {
@@ -98,16 +97,11 @@ import Foundation
     }
 
     private func handleUpdatedSpeakerphone() {
-        // TODO
-//        let category = AVAudioSession.sharedInstance().getCategory()
-//        if isSpeakerphoneEnabled {
-//            AVAudioSession.sharedInstance().setCategory(category, option: AVAudioSessionCategoryOptionDefaultToSpeaker)
-//        } else {
-        // Will this disable speaker?
-//            AVAudioSession.sharedInstance().setCategory(category)
-//        }
-
-        audioManager.toggleSpeakerPhone(isEnabled: isSpeakerphoneEnabled)
+        if isSpeakerphoneEnabled {
+            setAudioSession(category: AVAudioSessionCategoryPlayAndRecord, options: .defaultToSpeaker)
+        } else {
+            setAudioSession(category: AVAudioSessionCategoryPlayAndRecord)
+        }
     }
 
     // MARK: Helpers