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

webrtc/examples/objc/AppRTCMobile/ios/ARDMainViewController.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 "ARDMainViewController.h"
 
 #import <AVFoundation/AVFoundation.h>
 
 #import "WebRTC/RTCDispatcher.h"
 #import "WebRTC/RTCLogging.h"
 #import "webrtc/modules/audio_device/ios/objc/RTCAudioSession.h"
 #import "webrtc/modules/audio_device/ios/objc/RTCAudioSessionConfiguration.h"
 
 #import "ARDAppClient.h"
 #import "ARDMainView.h"
+#import "ARDMediaConstraintsModel.h"
+#import "ARDSettingsViewController.h"
 #import "ARDVideoCallViewController.h"
 
-static NSString *barButtonImageString = @"ic_settings_black_24dp.png";
+static NSString *const barButtonImageString = @"ic_settings_black_24dp.png";
 
 @interface ARDMainViewController () <
     ARDMainViewDelegate,
     ARDVideoCallViewControllerDelegate,
     RTCAudioSessionDelegate>
 @end
 
 @implementation ARDMainViewController {
   ARDMainView *_mainView;
   AVAudioPlayer *_audioPlayer;
@@ skipping 127 matching lines @@
   // WebRTC is done with the audio session. Restart playback.
   [RTCDispatcher dispatchAsyncOnType:RTCDispatcherTypeMain
                                block:^{
     RTCLog(@"audioSessionDidStopPlayOrRecord");
     [self restartAudioPlayerIfNeeded];
   }];
 }
 
 #pragma mark - Private
 - (void)showSettings:(id)sender {
+  ARDSettingsViewController *settingsController =
+      [[ARDSettingsViewController alloc] initWithStyle:UITableViewStylePlain
+                                 mediaConstraintsModel:[[ARDMediaConstraintsModel alloc] init]];
+  UINavigationController *navigationController =
+      [[UINavigationController alloc] initWithRootViewController:settingsController];
+  [self presentViewControllerAsModal:navigationController];
+}
+
+- (void)presentViewControllerAsModal:(UIViewController *)viewController {
+  [self presentViewController:viewController animated:YES completion:nil];
 }
 
 - (void)configureAudioSession {
   RTCAudioSessionConfiguration *configuration =
       [[RTCAudioSessionConfiguration alloc] init];
   configuration.category = AVAudioSessionCategoryAmbient;
   configuration.categoryOptions = AVAudioSessionCategoryOptionDuckOthers;
   configuration.mode = AVAudioSessionModeDefault;
 
   RTCAudioSession *session = [RTCAudioSession sharedInstance];
@@ skipping 35 matching lines @@
 - (void)showAlertWithMessage:(NSString*)message {
   UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:nil
                                                       message:message
                                                      delegate:nil
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];
   [alertView show];
 }
 
 @end