Revert of Rename AppRTCDemo on Android and iOS to AppRTCMobile

webrtc/examples/objc/AppRTCMobile/ARDAppClient.m

Index: webrtc/examples/objc/AppRTCMobile/ARDAppClient.m
diff --git a/webrtc/examples/objc/AppRTCMobile/ARDAppClient.m b/webrtc/examples/objc/AppRTCMobile/ARDAppClient.m
deleted file mode 100644
index 1020621cc1bd2b91340963ac20609688aaacd8f6..0000000000000000000000000000000000000000
--- a/webrtc/examples/objc/AppRTCMobile/ARDAppClient.m
+++ /dev/null
@@ -1,846 +0,0 @@
-/*
- *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#import "ARDAppClient+Internal.h"
-
-#import "WebRTC/RTCAVFoundationVideoSource.h"
-#import "WebRTC/RTCAudioTrack.h"
-#import "WebRTC/RTCConfiguration.h"
-#import "WebRTC/RTCFileLogger.h"
-#import "WebRTC/RTCIceServer.h"
-#import "WebRTC/RTCLogging.h"
-#import "WebRTC/RTCMediaConstraints.h"
-#import "WebRTC/RTCMediaStream.h"
-#import "WebRTC/RTCPeerConnectionFactory.h"
-#import "WebRTC/RTCRtpSender.h"
-#import "WebRTC/RTCTracing.h"
-
-#import "ARDAppEngineClient.h"
-#import "ARDCEODTURNClient.h"
-#import "ARDJoinResponse.h"
-#import "ARDMessageResponse.h"
-#import "ARDSDPUtils.h"
-#import "ARDSignalingMessage.h"
-#import "ARDUtilities.h"
-#import "ARDWebSocketChannel.h"
-#import "RTCIceCandidate+JSON.h"
-#import "RTCSessionDescription+JSON.h"
-
-static NSString * const kARDDefaultSTUNServerUrl =
-    @"stun:stun.l.google.com:19302";
-// TODO(tkchin): figure out a better username for CEOD statistics.
-static NSString * const kARDTurnRequestUrl =
-    @"https://computeengineondemand.appspot.com"
-    @"/turn?username=iapprtc&key=4080218913";
-
-static NSString * const kARDAppClientErrorDomain = @"ARDAppClient";
-static NSInteger const kARDAppClientErrorUnknown = -1;
-static NSInteger const kARDAppClientErrorRoomFull = -2;
-static NSInteger const kARDAppClientErrorCreateSDP = -3;
-static NSInteger const kARDAppClientErrorSetSDP = -4;
-static NSInteger const kARDAppClientErrorInvalidClient = -5;
-static NSInteger const kARDAppClientErrorInvalidRoom = -6;
-static NSString * const kARDMediaStreamId = @"ARDAMS";
-static NSString * const kARDAudioTrackId = @"ARDAMSa0";
-static NSString * const kARDVideoTrackId = @"ARDAMSv0";
-
-// TODO(tkchin): Add these as UI options.
-static BOOL const kARDAppClientEnableTracing = NO;
-static BOOL const kARDAppClientEnableRtcEventLog = YES;
-static int64_t const kARDAppClientAecDumpMaxSizeInBytes = 5e6;  // 5 MB.
-static int64_t const kARDAppClientRtcEventLogMaxSizeInBytes = 5e6;  // 5 MB.
-
-// We need a proxy to NSTimer because it causes a strong retain cycle. When
-// using the proxy, |invalidate| must be called before it properly deallocs.
-@interface ARDTimerProxy : NSObject
-
-- (instancetype)initWithInterval:(NSTimeInterval)interval
-                         repeats:(BOOL)repeats
-                    timerHandler:(void (^)(void))timerHandler;
-- (void)invalidate;
-
-@end
-
-@implementation ARDTimerProxy {
-  NSTimer *_timer;
-  void (^_timerHandler)(void);
-}
-
-- (instancetype)initWithInterval:(NSTimeInterval)interval
-                         repeats:(BOOL)repeats
-                    timerHandler:(void (^)(void))timerHandler {
-  NSParameterAssert(timerHandler);
-  if (self = [super init]) {
-    _timerHandler = timerHandler;
-    _timer = [NSTimer scheduledTimerWithTimeInterval:interval
-                                              target:self
-                                            selector:@selector(timerDidFire:)
-                                            userInfo:nil
-                                             repeats:repeats];
-  }
-  return self;
-}
-
-- (void)invalidate {
-  [_timer invalidate];
-}
-
-- (void)timerDidFire:(NSTimer *)timer {
-  _timerHandler();
-}
-
-@end
-
-@implementation ARDAppClient {
-  RTCFileLogger *_fileLogger;
-  ARDTimerProxy *_statsTimer;
-}
-
-@synthesize shouldGetStats = _shouldGetStats;
-@synthesize state = _state;
-@synthesize delegate = _delegate;
-@synthesize roomServerClient = _roomServerClient;
-@synthesize channel = _channel;
-@synthesize loopbackChannel = _loopbackChannel;
-@synthesize turnClient = _turnClient;
-@synthesize peerConnection = _peerConnection;
-@synthesize factory = _factory;
-@synthesize messageQueue = _messageQueue;
-@synthesize isTurnComplete = _isTurnComplete;
-@synthesize hasReceivedSdp  = _hasReceivedSdp;
-@synthesize roomId = _roomId;
-@synthesize clientId = _clientId;
-@synthesize isInitiator = _isInitiator;
-@synthesize iceServers = _iceServers;
-@synthesize webSocketURL = _websocketURL;
-@synthesize webSocketRestURL = _websocketRestURL;
-@synthesize defaultPeerConnectionConstraints =
-    _defaultPeerConnectionConstraints;
-@synthesize isLoopback = _isLoopback;
-@synthesize isAudioOnly = _isAudioOnly;
-@synthesize shouldMakeAecDump = _shouldMakeAecDump;
-@synthesize shouldUseLevelControl = _shouldUseLevelControl;
-
-- (instancetype)init {
-  if (self = [super init]) {
-    _roomServerClient = [[ARDAppEngineClient alloc] init];
-    NSURL *turnRequestURL = [NSURL URLWithString:kARDTurnRequestUrl];
-    _turnClient = [[ARDCEODTURNClient alloc] initWithURL:turnRequestURL];
-    [self configure];
-  }
-  return self;
-}
-
-- (instancetype)initWithDelegate:(id<ARDAppClientDelegate>)delegate {
-  if (self = [super init]) {
-    _roomServerClient = [[ARDAppEngineClient alloc] init];
-    _delegate = delegate;
-    NSURL *turnRequestURL = [NSURL URLWithString:kARDTurnRequestUrl];
-    _turnClient = [[ARDCEODTURNClient alloc] initWithURL:turnRequestURL];
-    [self configure];
-  }
-  return self;
-}
-
-// TODO(tkchin): Provide signaling channel factory interface so we can recreate
-// channel if we need to on network failure. Also, make this the default public
-// constructor.
-- (instancetype)initWithRoomServerClient:(id<ARDRoomServerClient>)rsClient
-                        signalingChannel:(id<ARDSignalingChannel>)channel
-                              turnClient:(id<ARDTURNClient>)turnClient
-                                delegate:(id<ARDAppClientDelegate>)delegate {
-  NSParameterAssert(rsClient);
-  NSParameterAssert(channel);
-  NSParameterAssert(turnClient);
-  if (self = [super init]) {
-    _roomServerClient = rsClient;
-    _channel = channel;
-    _turnClient = turnClient;
-    _delegate = delegate;
-    [self configure];
-  }
-  return self;
-}
-
-- (void)configure {
-  _factory = [[RTCPeerConnectionFactory alloc] init];
-  _messageQueue = [NSMutableArray array];
-  _iceServers = [NSMutableArray arrayWithObject:[self defaultSTUNServer]];
-  _fileLogger = [[RTCFileLogger alloc] init];
-  [_fileLogger start];
-}
-
-- (void)dealloc {
-  self.shouldGetStats = NO;
-  [self disconnect];
-}
-
-- (void)setShouldGetStats:(BOOL)shouldGetStats {
-  if (_shouldGetStats == shouldGetStats) {
-    return;
-  }
-  if (shouldGetStats) {
-    __weak ARDAppClient *weakSelf = self;
-    _statsTimer = [[ARDTimerProxy alloc] initWithInterval:1
-                                                  repeats:YES
-                                             timerHandler:^{
-      ARDAppClient *strongSelf = weakSelf;
-      [strongSelf.peerConnection statsForTrack:nil
-                              statsOutputLevel:RTCStatsOutputLevelDebug
-                             completionHandler:^(NSArray *stats) {
-        dispatch_async(dispatch_get_main_queue(), ^{
-          ARDAppClient *strongSelf = weakSelf;
-          [strongSelf.delegate appClient:strongSelf didGetStats:stats];
-        });
-      }];
-    }];
-  } else {
-    [_statsTimer invalidate];
-    _statsTimer = nil;
-  }
-  _shouldGetStats = shouldGetStats;
-}
-
-- (void)setState:(ARDAppClientState)state {
-  if (_state == state) {
-    return;
-  }
-  _state = state;
-  [_delegate appClient:self didChangeState:_state];
-}
-
-- (void)connectToRoomWithId:(NSString *)roomId
-                 isLoopback:(BOOL)isLoopback
-                isAudioOnly:(BOOL)isAudioOnly
-          shouldMakeAecDump:(BOOL)shouldMakeAecDump
-      shouldUseLevelControl:(BOOL)shouldUseLevelControl {
-  NSParameterAssert(roomId.length);
-  NSParameterAssert(_state == kARDAppClientStateDisconnected);
-  _isLoopback = isLoopback;
-  _isAudioOnly = isAudioOnly;
-  _shouldMakeAecDump = shouldMakeAecDump;
-  _shouldUseLevelControl = shouldUseLevelControl;
-  self.state = kARDAppClientStateConnecting;
-
-#if defined(WEBRTC_IOS)
-  if (kARDAppClientEnableTracing) {
-    NSString *filePath = [self documentsFilePathForFileName:@"webrtc-trace.txt"];
-    RTCStartInternalCapture(filePath);
-  }
-#endif
-
-  // Request TURN.
-  __weak ARDAppClient *weakSelf = self;
-  [_turnClient requestServersWithCompletionHandler:^(NSArray *turnServers,
-                                                     NSError *error) {
-    if (error) {
-      RTCLogError("Error retrieving TURN servers: %@",
-                  error.localizedDescription);
-    }
-    ARDAppClient *strongSelf = weakSelf;
-    [strongSelf.iceServers addObjectsFromArray:turnServers];
-    strongSelf.isTurnComplete = YES;
-    [strongSelf startSignalingIfReady];
-  }];
-
-  // Join room on room server.
-  [_roomServerClient joinRoomWithRoomId:roomId
-                             isLoopback:isLoopback
-      completionHandler:^(ARDJoinResponse *response, NSError *error) {
-    ARDAppClient *strongSelf = weakSelf;
-    if (error) {
-      [strongSelf.delegate appClient:strongSelf didError:error];
-      return;
-    }
-    NSError *joinError =
-        [[strongSelf class] errorForJoinResultType:response.result];
-    if (joinError) {
-      RTCLogError(@"Failed to join room:%@ on room server.", roomId);
-      [strongSelf disconnect];
-      [strongSelf.delegate appClient:strongSelf didError:joinError];
-      return;
-    }
-    RTCLog(@"Joined room:%@ on room server.", roomId);
-    strongSelf.roomId = response.roomId;
-    strongSelf.clientId = response.clientId;
-    strongSelf.isInitiator = response.isInitiator;
-    for (ARDSignalingMessage *message in response.messages) {
-      if (message.type == kARDSignalingMessageTypeOffer ||
-          message.type == kARDSignalingMessageTypeAnswer) {
-        strongSelf.hasReceivedSdp = YES;
-        [strongSelf.messageQueue insertObject:message atIndex:0];
-      } else {
-        [strongSelf.messageQueue addObject:message];
-      }
-    }
-    strongSelf.webSocketURL = response.webSocketURL;
-    strongSelf.webSocketRestURL = response.webSocketRestURL;
-    [strongSelf registerWithColliderIfReady];
-    [strongSelf startSignalingIfReady];
-  }];
-}
-
-- (void)disconnect {
-  if (_state == kARDAppClientStateDisconnected) {
-    return;
-  }
-  if (self.hasJoinedRoomServerRoom) {
-    [_roomServerClient leaveRoomWithRoomId:_roomId
-                                  clientId:_clientId
-                         completionHandler:nil];
-  }
-  if (_channel) {
-    if (_channel.state == kARDSignalingChannelStateRegistered) {
-      // Tell the other client we're hanging up.
-      ARDByeMessage *byeMessage = [[ARDByeMessage alloc] init];
-      [_channel sendMessage:byeMessage];
-    }
-    // Disconnect from collider.
-    _channel = nil;
-  }
-  _clientId = nil;
-  _roomId = nil;
-  _isInitiator = NO;
-  _hasReceivedSdp = NO;
-  _messageQueue = [NSMutableArray array];
-#if defined(WEBRTC_IOS)
-  [_factory stopAecDump];
-  [_peerConnection stopRtcEventLog];
-#endif
-  _peerConnection = nil;
-  self.state = kARDAppClientStateDisconnected;
-#if defined(WEBRTC_IOS)
-  RTCStopInternalCapture();
-#endif
-}
-
-#pragma mark - ARDSignalingChannelDelegate
-
-- (void)channel:(id<ARDSignalingChannel>)channel
-    didReceiveMessage:(ARDSignalingMessage *)message {
-  switch (message.type) {
-    case kARDSignalingMessageTypeOffer:
-    case kARDSignalingMessageTypeAnswer:
-      // Offers and answers must be processed before any other message, so we
-      // place them at the front of the queue.
-      _hasReceivedSdp = YES;
-      [_messageQueue insertObject:message atIndex:0];
-      break;
-    case kARDSignalingMessageTypeCandidate:
-    case kARDSignalingMessageTypeCandidateRemoval:
-      [_messageQueue addObject:message];
-      break;
-    case kARDSignalingMessageTypeBye:
-      // Disconnects can be processed immediately.
-      [self processSignalingMessage:message];
-      return;
-  }
-  [self drainMessageQueueIfReady];
-}
-
-- (void)channel:(id<ARDSignalingChannel>)channel
-    didChangeState:(ARDSignalingChannelState)state {
-  switch (state) {
-    case kARDSignalingChannelStateOpen:
-      break;
-    case kARDSignalingChannelStateRegistered:
-      break;
-    case kARDSignalingChannelStateClosed:
-    case kARDSignalingChannelStateError:
-      // TODO(tkchin): reconnection scenarios. Right now we just disconnect
-      // completely if the websocket connection fails.
-      [self disconnect];
-      break;
-  }
-}
-
-#pragma mark - RTCPeerConnectionDelegate
-// Callbacks for this delegate occur on non-main thread and need to be
-// dispatched back to main queue as needed.
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didChangeSignalingState:(RTCSignalingState)stateChanged {
-  RTCLog(@"Signaling state changed: %ld", (long)stateChanged);
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-          didAddStream:(RTCMediaStream *)stream {
-  dispatch_async(dispatch_get_main_queue(), ^{
-    RTCLog(@"Received %lu video tracks and %lu audio tracks",
-        (unsigned long)stream.videoTracks.count,
-        (unsigned long)stream.audioTracks.count);
-    if (stream.videoTracks.count) {
-      RTCVideoTrack *videoTrack = stream.videoTracks[0];
-      [_delegate appClient:self didReceiveRemoteVideoTrack:videoTrack];
-    }
-  });
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-       didRemoveStream:(RTCMediaStream *)stream {
-  RTCLog(@"Stream was removed.");
-}
-
-- (void)peerConnectionShouldNegotiate:(RTCPeerConnection *)peerConnection {
-  RTCLog(@"WARNING: Renegotiation needed but unimplemented.");
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didChangeIceConnectionState:(RTCIceConnectionState)newState {
-  RTCLog(@"ICE state changed: %ld", (long)newState);
-  dispatch_async(dispatch_get_main_queue(), ^{
-    [_delegate appClient:self didChangeConnectionState:newState];
-  });
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didChangeIceGatheringState:(RTCIceGatheringState)newState {
-  RTCLog(@"ICE gathering state changed: %ld", (long)newState);
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didGenerateIceCandidate:(RTCIceCandidate *)candidate {
-  dispatch_async(dispatch_get_main_queue(), ^{
-    ARDICECandidateMessage *message =
-        [[ARDICECandidateMessage alloc] initWithCandidate:candidate];
-    [self sendSignalingMessage:message];
-  });
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didRemoveIceCandidates:(NSArray<RTCIceCandidate *> *)candidates {
-  dispatch_async(dispatch_get_main_queue(), ^{
-    ARDICECandidateRemovalMessage *message =
-        [[ARDICECandidateRemovalMessage alloc]
-            initWithRemovedCandidates:candidates];
-    [self sendSignalingMessage:message];
-  });
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didOpenDataChannel:(RTCDataChannel *)dataChannel {
-}
-
-#pragma mark - RTCSessionDescriptionDelegate
-// Callbacks for this delegate occur on non-main thread and need to be
-// dispatched back to main queue as needed.
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didCreateSessionDescription:(RTCSessionDescription *)sdp
-                          error:(NSError *)error {
-  dispatch_async(dispatch_get_main_queue(), ^{
-    if (error) {
-      RTCLogError(@"Failed to create session description. Error: %@", error);
-      [self disconnect];
-      NSDictionary *userInfo = @{
-        NSLocalizedDescriptionKey: @"Failed to create session description.",
-      };
-      NSError *sdpError =
-          [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
-                                     code:kARDAppClientErrorCreateSDP
-                                 userInfo:userInfo];
-      [_delegate appClient:self didError:sdpError];
-      return;
-    }
-    // Prefer H264 if available.
-    RTCSessionDescription *sdpPreferringH264 =
-        [ARDSDPUtils descriptionForDescription:sdp
-                           preferredVideoCodec:@"H264"];
-    __weak ARDAppClient *weakSelf = self;
-    [_peerConnection setLocalDescription:sdpPreferringH264
-                       completionHandler:^(NSError *error) {
-      ARDAppClient *strongSelf = weakSelf;
-      [strongSelf peerConnection:strongSelf.peerConnection
-          didSetSessionDescriptionWithError:error];
-    }];
-    ARDSessionDescriptionMessage *message =
-        [[ARDSessionDescriptionMessage alloc]
-            initWithDescription:sdpPreferringH264];
-    [self sendSignalingMessage:message];
-  });
-}
-
-- (void)peerConnection:(RTCPeerConnection *)peerConnection
-    didSetSessionDescriptionWithError:(NSError *)error {
-  dispatch_async(dispatch_get_main_queue(), ^{
-    if (error) {
-      RTCLogError(@"Failed to set session description. Error: %@", error);
-      [self disconnect];
-      NSDictionary *userInfo = @{
-        NSLocalizedDescriptionKey: @"Failed to set session description.",
-      };
-      NSError *sdpError =
-          [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
-                                     code:kARDAppClientErrorSetSDP
-                                 userInfo:userInfo];
-      [_delegate appClient:self didError:sdpError];
-      return;
-    }
-    // If we're answering and we've just set the remote offer we need to create
-    // an answer and set the local description.
-    if (!_isInitiator && !_peerConnection.localDescription) {
-      RTCMediaConstraints *constraints = [self defaultAnswerConstraints];
-      __weak ARDAppClient *weakSelf = self;
-      [_peerConnection answerForConstraints:constraints
-                          completionHandler:^(RTCSessionDescription *sdp,
-                                              NSError *error) {
-        ARDAppClient *strongSelf = weakSelf;
-        [strongSelf peerConnection:strongSelf.peerConnection
-            didCreateSessionDescription:sdp
-                                  error:error];
-      }];
-    }
-  });
-}
-
-#pragma mark - Private
-
-#if defined(WEBRTC_IOS)
-
-- (NSString *)documentsFilePathForFileName:(NSString *)fileName {
-  NSParameterAssert(fileName.length);
-  NSArray *paths = NSSearchPathForDirectoriesInDomains(
-      NSDocumentDirectory, NSUserDomainMask, YES);
-  NSString *documentsDirPath = paths.firstObject;
-  NSString *filePath =
-      [documentsDirPath stringByAppendingPathComponent:fileName];
-  return filePath;
-}
-
-#endif
-
-- (BOOL)hasJoinedRoomServerRoom {
-  return _clientId.length;
-}
-
-// Begins the peer connection connection process if we have both joined a room
-// on the room server and tried to obtain a TURN server. Otherwise does nothing.
-// A peer connection object will be created with a stream that contains local
-// audio and video capture. If this client is the caller, an offer is created as
-// well, otherwise the client will wait for an offer to arrive.
-- (void)startSignalingIfReady {
-  if (!_isTurnComplete || !self.hasJoinedRoomServerRoom) {
-    return;
-  }
-  self.state = kARDAppClientStateConnected;
-
-  // Create peer connection.
-  RTCMediaConstraints *constraints = [self defaultPeerConnectionConstraints];
-  RTCConfiguration *config = [[RTCConfiguration alloc] init];
-  config.iceServers = _iceServers;
-  _peerConnection = [_factory peerConnectionWithConfiguration:config
-                                                  constraints:constraints
-                                                     delegate:self];
-  // Create AV senders.
-  [self createAudioSender];
-  [self createVideoSender];
-  if (_isInitiator) {
-    // Send offer.
-    __weak ARDAppClient *weakSelf = self;
-    [_peerConnection offerForConstraints:[self defaultOfferConstraints]
-                       completionHandler:^(RTCSessionDescription *sdp,
-                                           NSError *error) {
-      ARDAppClient *strongSelf = weakSelf;
-      [strongSelf peerConnection:strongSelf.peerConnection
-          didCreateSessionDescription:sdp
-                                error:error];
-    }];
-  } else {
-    // Check if we've received an offer.
-    [self drainMessageQueueIfReady];
-  }
-#if defined(WEBRTC_IOS)
-  // Start event log.
-  if (kARDAppClientEnableRtcEventLog) {
-    NSString *filePath = [self documentsFilePathForFileName:@"webrtc-rtceventlog"];
-    if (![_peerConnection startRtcEventLogWithFilePath:filePath
-                                 maxSizeInBytes:kARDAppClientRtcEventLogMaxSizeInBytes]) {
-      RTCLogError(@"Failed to start event logging.");
-    }
-  }
-
-  // Start aecdump diagnostic recording.
-  if (_shouldMakeAecDump) {
-    NSString *filePath = [self documentsFilePathForFileName:@"webrtc-audio.aecdump"];
-    if (![_factory startAecDumpWithFilePath:filePath
-                             maxSizeInBytes:kARDAppClientAecDumpMaxSizeInBytes]) {
-      RTCLogError(@"Failed to start aec dump.");
-    }
-  }
-#endif
-}
-
-// Processes the messages that we've received from the room server and the
-// signaling channel. The offer or answer message must be processed before other
-// signaling messages, however they can arrive out of order. Hence, this method
-// only processes pending messages if there is a peer connection object and
-// if we have received either an offer or answer.
-- (void)drainMessageQueueIfReady {
-  if (!_peerConnection || !_hasReceivedSdp) {
-    return;
-  }
-  for (ARDSignalingMessage *message in _messageQueue) {
-    [self processSignalingMessage:message];
-  }
-  [_messageQueue removeAllObjects];
-}
-
-// Processes the given signaling message based on its type.
-- (void)processSignalingMessage:(ARDSignalingMessage *)message {
-  NSParameterAssert(_peerConnection ||
-      message.type == kARDSignalingMessageTypeBye);
-  switch (message.type) {
-    case kARDSignalingMessageTypeOffer:
-    case kARDSignalingMessageTypeAnswer: {
-      ARDSessionDescriptionMessage *sdpMessage =
-          (ARDSessionDescriptionMessage *)message;
-      RTCSessionDescription *description = sdpMessage.sessionDescription;
-      // Prefer H264 if available.
-      RTCSessionDescription *sdpPreferringH264 =
-          [ARDSDPUtils descriptionForDescription:description
-                             preferredVideoCodec:@"H264"];
-      __weak ARDAppClient *weakSelf = self;
-      [_peerConnection setRemoteDescription:sdpPreferringH264
-                          completionHandler:^(NSError *error) {
-        ARDAppClient *strongSelf = weakSelf;
-        [strongSelf peerConnection:strongSelf.peerConnection
-            didSetSessionDescriptionWithError:error];
-      }];
-      break;
-    }
-    case kARDSignalingMessageTypeCandidate: {
-      ARDICECandidateMessage *candidateMessage =
-          (ARDICECandidateMessage *)message;
-      [_peerConnection addIceCandidate:candidateMessage.candidate];
-      break;
-    }
-    case kARDSignalingMessageTypeCandidateRemoval: {
-      ARDICECandidateRemovalMessage *candidateMessage =
-          (ARDICECandidateRemovalMessage *)message;
-      [_peerConnection removeIceCandidates:candidateMessage.candidates];
-      break;
-    }
-    case kARDSignalingMessageTypeBye:
-      // Other client disconnected.
-      // TODO(tkchin): support waiting in room for next client. For now just
-      // disconnect.
-      [self disconnect];
-      break;
-  }
-}
-
-// Sends a signaling message to the other client. The caller will send messages
-// through the room server, whereas the callee will send messages over the
-// signaling channel.
-- (void)sendSignalingMessage:(ARDSignalingMessage *)message {
-  if (_isInitiator) {
-    __weak ARDAppClient *weakSelf = self;
-    [_roomServerClient sendMessage:message
-                         forRoomId:_roomId
-                          clientId:_clientId
-                 completionHandler:^(ARDMessageResponse *response,
-                                     NSError *error) {
-      ARDAppClient *strongSelf = weakSelf;
-      if (error) {
-        [strongSelf.delegate appClient:strongSelf didError:error];
-        return;
-      }
-      NSError *messageError =
-          [[strongSelf class] errorForMessageResultType:response.result];
-      if (messageError) {
-        [strongSelf.delegate appClient:strongSelf didError:messageError];
-        return;
-      }
-    }];
-  } else {
-    [_channel sendMessage:message];
-  }
-}
-
-- (RTCRtpSender *)createVideoSender {
-  RTCRtpSender *sender =
-      [_peerConnection senderWithKind:kRTCMediaStreamTrackKindVideo
-                             streamId:kARDMediaStreamId];
-  RTCVideoTrack *track = [self createLocalVideoTrack];
-  if (track) {
-    sender.track = track;
-    [_delegate appClient:self didReceiveLocalVideoTrack:track];
-  }
-  return sender;
-}
-
-- (RTCRtpSender *)createAudioSender {
-  RTCMediaConstraints *constraints = [self defaultMediaAudioConstraints];
-  RTCAudioSource *source = [_factory audioSourceWithConstraints:constraints];
-  RTCAudioTrack *track = [_factory audioTrackWithSource:source
-                                                trackId:kARDAudioTrackId];
-  RTCRtpSender *sender =
-      [_peerConnection senderWithKind:kRTCMediaStreamTrackKindAudio
-                             streamId:kARDMediaStreamId];
-  sender.track = track;
-  return sender;
-}
-
-- (RTCVideoTrack *)createLocalVideoTrack {
-  RTCVideoTrack* localVideoTrack = nil;
-  // The iOS simulator doesn't provide any sort of camera capture
-  // support or emulation (http://goo.gl/rHAnC1) so don't bother
-  // trying to open a local stream.
-#if !TARGET_IPHONE_SIMULATOR
-  if (!_isAudioOnly) {
-    RTCMediaConstraints *mediaConstraints =
-        [self defaultMediaStreamConstraints];
-    RTCAVFoundationVideoSource *source =
-        [_factory avFoundationVideoSourceWithConstraints:mediaConstraints];
-    localVideoTrack =
-        [_factory videoTrackWithSource:source
-                               trackId:kARDVideoTrackId];
-  }
-#endif
-  return localVideoTrack;
-}
-
-#pragma mark - Collider methods
-
-- (void)registerWithColliderIfReady {
-  if (!self.hasJoinedRoomServerRoom) {
-    return;
-  }
-  // Open WebSocket connection.
-  if (!_channel) {
-    _channel =
-        [[ARDWebSocketChannel alloc] initWithURL:_websocketURL
-                                         restURL:_websocketRestURL
-                                        delegate:self];
-    if (_isLoopback) {
-      _loopbackChannel =
-          [[ARDLoopbackWebSocketChannel alloc] initWithURL:_websocketURL
-                                                   restURL:_websocketRestURL];
-    }
-  }
-  [_channel registerForRoomId:_roomId clientId:_clientId];
-  if (_isLoopback) {
-    [_loopbackChannel registerForRoomId:_roomId clientId:@"LOOPBACK_CLIENT_ID"];
-  }
-}
-
-#pragma mark - Defaults
-
- - (RTCMediaConstraints *)defaultMediaAudioConstraints {
-   NSString *valueLevelControl = _shouldUseLevelControl ?
-       kRTCMediaConstraintsValueTrue : kRTCMediaConstraintsValueFalse;
-   NSDictionary *mandatoryConstraints = @{ kRTCMediaConstraintsLevelControl : valueLevelControl };
-   RTCMediaConstraints* constraints =
-       [[RTCMediaConstraints alloc]  initWithMandatoryConstraints:mandatoryConstraints
-                                              optionalConstraints:nil];
-   return constraints;
-}
-
-- (RTCMediaConstraints *)defaultMediaStreamConstraints {
-  RTCMediaConstraints* constraints =
-      [[RTCMediaConstraints alloc]
-          initWithMandatoryConstraints:nil
-                   optionalConstraints:nil];
-  return constraints;
-}
-
-- (RTCMediaConstraints *)defaultAnswerConstraints {
-  return [self defaultOfferConstraints];
-}
-
-- (RTCMediaConstraints *)defaultOfferConstraints {
-  NSDictionary *mandatoryConstraints = @{
-    @"OfferToReceiveAudio" : @"true",
-    @"OfferToReceiveVideo" : @"true"
-  };
-  RTCMediaConstraints* constraints =
-      [[RTCMediaConstraints alloc]
-          initWithMandatoryConstraints:mandatoryConstraints
-                   optionalConstraints:nil];
-  return constraints;
-}
-
-- (RTCMediaConstraints *)defaultPeerConnectionConstraints {
-  if (_defaultPeerConnectionConstraints) {
-    return _defaultPeerConnectionConstraints;
-  }
-  NSString *value = _isLoopback ? @"false" : @"true";
-  NSDictionary *optionalConstraints = @{ @"DtlsSrtpKeyAgreement" : value };
-  RTCMediaConstraints* constraints =
-      [[RTCMediaConstraints alloc]
-          initWithMandatoryConstraints:nil
-                   optionalConstraints:optionalConstraints];
-  return constraints;
-}
-
-- (RTCIceServer *)defaultSTUNServer {
-  return [[RTCIceServer alloc] initWithURLStrings:@[kARDDefaultSTUNServerUrl]
-                                         username:@""
-                                       credential:@""];
-}
-
-#pragma mark - Errors
-
-+ (NSError *)errorForJoinResultType:(ARDJoinResultType)resultType {
-  NSError *error = nil;
-  switch (resultType) {
-    case kARDJoinResultTypeSuccess:
-      break;
-    case kARDJoinResultTypeUnknown: {
-      error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
-                                         code:kARDAppClientErrorUnknown
-                                     userInfo:@{
-        NSLocalizedDescriptionKey: @"Unknown error.",
-      }];
-      break;
-    }
-    case kARDJoinResultTypeFull: {
-      error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
-                                         code:kARDAppClientErrorRoomFull
-                                     userInfo:@{
-        NSLocalizedDescriptionKey: @"Room is full.",
-      }];
-      break;
-    }
-  }
-  return error;
-}
-
-+ (NSError *)errorForMessageResultType:(ARDMessageResultType)resultType {
-  NSError *error = nil;
-  switch (resultType) {
-    case kARDMessageResultTypeSuccess:
-      break;
-    case kARDMessageResultTypeUnknown:
-      error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
-                                         code:kARDAppClientErrorUnknown
-                                     userInfo:@{
-        NSLocalizedDescriptionKey: @"Unknown error.",
-      }];
-      break;
-    case kARDMessageResultTypeInvalidClient:
-      error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
-                                         code:kARDAppClientErrorInvalidClient
-                                     userInfo:@{
-        NSLocalizedDescriptionKey: @"Invalid client.",
-      }];
-      break;
-    case kARDMessageResultTypeInvalidRoom:
-      error = [[NSError alloc] initWithDomain:kARDAppClientErrorDomain
-                                         code:kARDAppClientErrorInvalidRoom
-                                     userInfo:@{
-        NSLocalizedDescriptionKey: @"Invalid room.",
-      }];
-      break;
-  }
-  return error;
-}
-
-@end