Add setting to AppRTCMobile for iOS, that can change capture resolution.

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.
  */
 
 #import "ARDVideoCallViewController.h"
 
 #import "webrtc/modules/audio_device/ios/objc/RTCAudioSession.h"
 
+#import "ARDAppClient.h"
+#import "ARDMediaConstraintsModel.h"
+#import "ARDVideoCallView.h"
 #import "WebRTC/RTCAVFoundationVideoSource.h"
 #import "WebRTC/RTCDispatcher.h"
 #import "WebRTC/RTCLogging.h"
-
-#import "ARDAppClient.h"
-#import "ARDVideoCallView.h"
+#import "WebRTC/RTCMediaConstraints.h"
 
 @interface ARDVideoCallViewController () <ARDAppClientDelegate,
     ARDVideoCallViewDelegate>
 @property(nonatomic, strong) RTCVideoTrack *localVideoTrack;
 @property(nonatomic, strong) RTCVideoTrack *remoteVideoTrack;
 @property(nonatomic, readonly) ARDVideoCallView *videoCallView;
 @end
 
 @implementation ARDVideoCallViewController {
   ARDAppClient *_client;
   RTCVideoTrack *_remoteVideoTrack;
   RTCVideoTrack *_localVideoTrack;
   AVAudioSessionPortOverride _portOverride;
 }
 
 @synthesize videoCallView = _videoCallView;
 @synthesize delegate = _delegate;
 
 - (instancetype)initForRoom:(NSString *)room
                  isLoopback:(BOOL)isLoopback
                 isAudioOnly:(BOOL)isAudioOnly
           shouldMakeAecDump:(BOOL)shouldMakeAecDump
       shouldUseLevelControl:(BOOL)shouldUseLevelControl
                    delegate:(id<ARDVideoCallViewControllerDelegate>)delegate {
   if (self = [super init]) {
     _delegate = delegate;
     _client = [[ARDAppClient alloc] initWithDelegate:self];
+    ARDMediaConstraintsModel *mediaConstraintsModel = [[ARDMediaConstraintsModel alloc] init];
+    RTCMediaConstraints *cameraConstraints = [[RTCMediaConstraints alloc]
+        initWithMandatoryConstraints:nil
+                 optionalConstraints:[mediaConstraintsModel
+                                         currentMediaConstraintFromStoreAsRTCDictionary]];
+    [_client setCameraConstraints:cameraConstraints];
     [_client connectToRoomWithId:room
                       isLoopback:isLoopback
                      isAudioOnly:isAudioOnly
                shouldMakeAecDump:shouldMakeAecDump
            shouldUseLevelControl:shouldUseLevelControl];
   }
   return self;
 }
 
 - (void)loadView {
@@ skipping 155 matching lines @@
 - (void)showAlertWithMessage:(NSString*)message {
   UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:nil
                                                       message:message
                                                      delegate:nil
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];
   [alertView show];
 }
 
 @end