Moving iOS Audio Device to sdk.

This change forks the existing iOS audio device module and audio device
from modules/audio_device/ into sdk/objc/Framework. It also updates
RTCPeerConnectionFactory to use the forked implementation.

The unit tests are re-implemented as XCTests.

(was: https://webrtc-review.googlesource.com/c/src/+/67300)

Bug: webrtc:9120
Change-Id: I07340505137b16c2dd487569ad0112f984557bba
Reviewed-on: https://webrtc-review.googlesource.com/75125
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Peter Hanspers <peterhanspers@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23208}

sdk/objc/Framework/Classes/Audio/RTCNativeAudioSessionDelegateAdapter.h

@@ -0,0 +1,34 @@
+/*
+ *  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 "sdk/objc/Framework/Headers/WebRTC/RTCAudioSession.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+namespace webrtc {
+class AudioSessionObserver;
+}
+
+/** Adapter that forwards RTCAudioSessionDelegate calls to the appropriate
+ *  methods on the AudioSessionObserver.
+ */
+@interface RTCNativeAudioSessionDelegateAdapter : NSObject <RTCAudioSessionDelegate>
+
+- (instancetype)init NS_UNAVAILABLE;
+
+/** |observer| is a raw pointer and should be kept alive
+ *  for this object's lifetime.
+ */
+- (instancetype)initWithObserver:(webrtc::AudioSessionObserver *)observer
+    NS_DESIGNATED_INITIALIZER;
+
+@end
+
+NS_ASSUME_NONNULL_END

sdk/objc/Framework/Classes/Audio/RTCNativeAudioSessionDelegateAdapter.mm

@@ -0,0 +1,89 @@
+/*
+ *  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 "RTCNativeAudioSessionDelegateAdapter.h"
+
+#include "sdk/objc/Framework/Native/src/audio/audio_session_observer.h"
+
+#import "WebRTC/RTCLogging.h"
+
+@implementation RTCNativeAudioSessionDelegateAdapter {
+  webrtc::AudioSessionObserver *_observer;
+}
+
+- (instancetype)initWithObserver:(webrtc::AudioSessionObserver *)observer {
+  RTC_DCHECK(observer);
+  if (self = [super init]) {
+    _observer = observer;
+  }
+  return self;
+}
+
+#pragma mark - RTCAudioSessionDelegate
+
+- (void)audioSessionDidBeginInterruption:(RTCAudioSession *)session {
+  _observer->OnInterruptionBegin();
+}
+
+- (void)audioSessionDidEndInterruption:(RTCAudioSession *)session
+                   shouldResumeSession:(BOOL)shouldResumeSession {
+  _observer->OnInterruptionEnd();
+}
+
+- (void)audioSessionDidChangeRoute:(RTCAudioSession *)session
+           reason:(AVAudioSessionRouteChangeReason)reason
+    previousRoute:(AVAudioSessionRouteDescription *)previousRoute {
+  switch (reason) {
+    case AVAudioSessionRouteChangeReasonUnknown:
+    case AVAudioSessionRouteChangeReasonNewDeviceAvailable:
+    case AVAudioSessionRouteChangeReasonOldDeviceUnavailable:
+    case AVAudioSessionRouteChangeReasonCategoryChange:
+      // It turns out that we see a category change (at least in iOS 9.2)
+      // when making a switch from a BT device to e.g. Speaker using the
+      // iOS Control Center and that we therefore must check if the sample
+      // rate has changed. And if so is the case, restart the audio unit.
+    case AVAudioSessionRouteChangeReasonOverride:
+    case AVAudioSessionRouteChangeReasonWakeFromSleep:
+    case AVAudioSessionRouteChangeReasonNoSuitableRouteForCategory:
+      _observer->OnValidRouteChange();
+      break;
+    case AVAudioSessionRouteChangeReasonRouteConfigurationChange:
+      // The set of input and output ports has not changed, but their
+      // configuration has, e.g., a port’s selected data source has
+      // changed. Ignore this type of route change since we are focusing
+      // on detecting headset changes.
+      RTCLog(@"Ignoring RouteConfigurationChange");
+      break;
+  }
+}
+
+- (void)audioSessionMediaServerTerminated:(RTCAudioSession *)session {
+}
+
+- (void)audioSessionMediaServerReset:(RTCAudioSession *)session {
+}
+
+- (void)audioSession:(RTCAudioSession *)session
+    didChangeCanPlayOrRecord:(BOOL)canPlayOrRecord {
+  _observer->OnCanPlayOrRecordChange(canPlayOrRecord);
+}
+
+- (void)audioSessionDidStartPlayOrRecord:(RTCAudioSession *)session {
+}
+
+- (void)audioSessionDidStopPlayOrRecord:(RTCAudioSession *)session {
+}
+
+- (void)audioSession:(RTCAudioSession *)audioSession
+    didChangeOutputVolume:(float)outputVolume {
+  _observer->OnChangedOutputVolume();
+}
+
+@end

sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm

@@ -38,6 +38,10 @@
 #include "sdk/objc/Framework/Native/src/objc_video_encoder_factory.h"
 #endif
 
+#if defined(WEBRTC_IOS)
+#import "sdk/objc/Framework/Native/api/audio_device_module.h"
+#endif
+
 // Adding the nogncheck to disable the including header check.
 // The no-media version PeerConnectionFactory doesn't depend on media related
 // C++ target.
@@ -55,6 +59,14 @@
 
 @synthesize nativeFactory = _nativeFactory;
 
+- (rtc::scoped_refptr<webrtc::AudioDeviceModule>)audioDeviceModule {
+#if defined(WEBRTC_IOS)
+  return webrtc::CreateAudioDeviceModule();
+#else
+  return nullptr;
+#endif
+}
+
 - (instancetype)init {
 #ifdef HAVE_NO_MEDIA
   return [self initWithNoMedia];
@@ -65,7 +77,7 @@
                                                      [[RTCVideoEncoderFactoryH264 alloc] init])
                        nativeVideoDecoderFactory:webrtc::ObjCToNativeVideoDecoderFactory(
                                                      [[RTCVideoDecoderFactoryH264 alloc] init])
-                               audioDeviceModule:nullptr
+                               audioDeviceModule:[self audioDeviceModule]
                            audioProcessingModule:nullptr];
 #endif
 }
@@ -87,7 +99,7 @@
                        nativeAudioDecoderFactory:webrtc::CreateBuiltinAudioDecoderFactory()
                        nativeVideoEncoderFactory:std::move(native_encoder_factory)
                        nativeVideoDecoderFactory:std::move(native_decoder_factory)
-                               audioDeviceModule:nullptr
+                               audioDeviceModule:[self audioDeviceModule]
                            audioProcessingModule:nullptr];
 #endif
 }