Add video codec setting to AppRTCMobile on iOS.

webrtc/examples/objc/AppRTCMobile/ios/ARDVideoCallViewController.m

 /*
  *  Copyright 2015 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.
  */
 
@@ skipping 33 matching lines @@
       shouldUseLevelControl:(BOOL)shouldUseLevelControl
                    delegate:(id<ARDVideoCallViewControllerDelegate>)delegate {
   if (self = [super init]) {
     _delegate = delegate;
     _client = [[ARDAppClient alloc] initWithDelegate:self];
     ARDSettingsModel *settingsModel = [[ARDSettingsModel alloc] init];
     RTCMediaConstraints *cameraConstraints = [[RTCMediaConstraints alloc]
         initWithMandatoryConstraints:nil
                  optionalConstraints:[settingsModel
                                          currentMediaConstraintFromStoreAsRTCDictionary]];
+    [_client setVideoCodec:[settingsModel currentVideoCodecSettingFromStore]];

[kthelgason, 2017/03/10 10:41:44]

I realize that this is just copying the style below but it should rather be
`client.videoCodec =` for properties.

Also, consider making the property read-only and passing it in the initializer.
Seems safer to me since we make the assumption in ARDAppClient that it's always
set.

[sakal, 2017/03/10 11:23:13]

Done.

     [_client setMaxBitrate:[settingsModel currentMaxBitrateSettingFromStore]];
     [_client setCameraConstraints:cameraConstraints];
     [_client connectToRoomWithId:room
                       isLoopback:isLoopback
                      isAudioOnly:isAudioOnly
                shouldMakeAecDump:shouldMakeAecDump
            shouldUseLevelControl:shouldUseLevelControl];
   }
   return self;
 }
@@ skipping 157 matching lines @@
 - (void)showAlertWithMessage:(NSString*)message {
   UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:nil
                                                       message:message
                                                      delegate:nil
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];
   [alertView show];
 }
 
 @end