Broadcast extension for AppRTCMobile on iOS

This provides an environment for testing out using WebRTC from an iOS
extension. It implements a ReplayKit broadcast extension for live
streaming games and screensharing.

The extension is only supported on iOS 11+ and is guarded by a build
flag.

Bug: webrtc:9335
Change-Id: Id218d6c73ef7599f5953c5a1e0e62e5d0dc4f10b
Reviewed-on: https://webrtc-review.googlesource.com/80000
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23504}

examples/objc/AppRTCMobile/ios/broadcast_extension/ARDBroadcastSetupViewController.m

@@ -0,0 +1,107 @@
+/*
+ *  Copyright 2018 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 "ARDBroadcastSetupViewController.h"
+
+@implementation ARDBroadcastSetupViewController {
+  UITextField *_roomNameField;
+}
+
+- (void)loadView {
+  UIView *view = [[UIView alloc] initWithFrame:CGRectZero];
+  view.backgroundColor = [UIColor colorWithWhite:1.0 alpha:0.7];
+
+  UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Icon-180"]];
+  imageView.translatesAutoresizingMaskIntoConstraints = NO;
+  [view addSubview:imageView];
+
+  _roomNameField = [[UITextField alloc] initWithFrame:CGRectZero];
+  _roomNameField.borderStyle = UITextBorderStyleRoundedRect;
+  _roomNameField.font = [UIFont systemFontOfSize:14.0];
+  _roomNameField.translatesAutoresizingMaskIntoConstraints = NO;
+  _roomNameField.placeholder = @"Room name";
+  _roomNameField.returnKeyType = UIReturnKeyDone;
+  _roomNameField.delegate = self;
+  [view addSubview:_roomNameField];
+
+  UIButton *doneButton = [UIButton buttonWithType:UIButtonTypeSystem];
+  doneButton.translatesAutoresizingMaskIntoConstraints = NO;
+  doneButton.titleLabel.font = [UIFont systemFontOfSize:20.0];
+  [doneButton setTitle:@"Done" forState:UIControlStateNormal];
+  [doneButton addTarget:self
+                 action:@selector(userDidFinishSetup)
+       forControlEvents:UIControlEventTouchUpInside];
+  [view addSubview:doneButton];
+
+  UIButton *cancelButton = [UIButton buttonWithType:UIButtonTypeSystem];
+  cancelButton.translatesAutoresizingMaskIntoConstraints = NO;
+  cancelButton.titleLabel.font = [UIFont systemFontOfSize:20.0];
+  [cancelButton setTitle:@"Cancel" forState:UIControlStateNormal];
+  [cancelButton addTarget:self
+                   action:@selector(userDidCancelSetup)
+         forControlEvents:UIControlEventTouchUpInside];
+  [view addSubview:cancelButton];
+
+  UILayoutGuide *margin = view.layoutMarginsGuide;
+  [imageView.widthAnchor constraintEqualToConstant:60.0].active = YES;
+  [imageView.heightAnchor constraintEqualToConstant:60.0].active = YES;
+  [imageView.topAnchor constraintEqualToAnchor:margin.topAnchor constant:20].active = YES;
+  [imageView.centerXAnchor constraintEqualToAnchor:view.centerXAnchor].active = YES;
+
+  [_roomNameField.leadingAnchor constraintEqualToAnchor:margin.leadingAnchor].active = YES;
+  [_roomNameField.topAnchor constraintEqualToAnchor:imageView.bottomAnchor constant:20].active =
+      YES;
+  [_roomNameField.trailingAnchor constraintEqualToAnchor:margin.trailingAnchor].active = YES;
+
+  [doneButton.leadingAnchor constraintEqualToAnchor:margin.leadingAnchor].active = YES;
+  [doneButton.bottomAnchor constraintEqualToAnchor:margin.bottomAnchor constant:-20].active = YES;
+
+  [cancelButton.trailingAnchor constraintEqualToAnchor:margin.trailingAnchor].active = YES;
+  [cancelButton.bottomAnchor constraintEqualToAnchor:margin.bottomAnchor constant:-20].active = YES;
+
+  UITapGestureRecognizer *tgr =
+      [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(didTap:)];
+  [view addGestureRecognizer:tgr];
+
+  self.view = view;
+}
+
+- (IBAction)didTap:(id)sender {
+  [self.view endEditing:YES];
+}
+
+- (void)userDidFinishSetup {
+  // URL of the resource where broadcast can be viewed that will be returned to the application
+  NSURL *broadcastURL = [NSURL
+      URLWithString:[NSString stringWithFormat:@"https://appr.tc/r/%@", _roomNameField.text]];
+
+  // Dictionary with setup information that will be provided to broadcast extension when broadcast
+  // is started
+  NSDictionary *setupInfo = @{@"roomName" : _roomNameField.text};
+
+  // Tell ReplayKit that the extension is finished setting up and can begin broadcasting
+  [self.extensionContext completeRequestWithBroadcastURL:broadcastURL setupInfo:setupInfo];
+}
+
+- (void)userDidCancelSetup {
+  // Tell ReplayKit that the extension was cancelled by the user
+  [self.extensionContext cancelRequestWithError:[NSError errorWithDomain:@"com.google.AppRTCMobile"
+                                                                    code:-1
+                                                                userInfo:nil]];
+}
+
+#pragma mark - UITextFieldDelegate
+
+- (BOOL)textFieldShouldReturn:(UITextField *)textField {
+  [self userDidFinishSetup];
+  return YES;
+}
+
+@end