Ensures that ADM for Android and iOS uses identical states when stopping audio

webrtc/modules/audio_device/ios/audio_device_ios.mm

Index: webrtc/modules/audio_device/ios/audio_device_ios.mm
diff --git a/webrtc/modules/audio_device/ios/audio_device_ios.mm b/webrtc/modules/audio_device/ios/audio_device_ios.mm
index 3a745a4b459cd6b6522a58cd3acfca21517debac..8d03ba32f38e2cb71cb1173985a2ba3afc8cccba 100644
--- a/webrtc/modules/audio_device/ios/audio_device_ios.mm
+++ b/webrtc/modules/audio_device/ios/audio_device_ios.mm
@@ -217,11 +217,7 @@ int32_t AudioDeviceIOS::StartPlayout() {
 int32_t AudioDeviceIOS::StopPlayout() {
   LOGI() << "StopPlayout";
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
-  if (!play_is_initialized_) {
-    return 0;
-  }
-  if (!playing_) {
-    play_is_initialized_ = false;
+  if (!play_is_initialized_ || !playing_) {

[sophiechang-webrtc, 2016/09/21 10:43:54]

as mentioned offline, i think it would be good to merge the rec_is_initialized_
and play_is_initialized_ to some sort of audio_is_initialized_ variable since
they both just control the audio unit. and also only set audio_is_initialized_
to false when you call ShutdownPlayOrRecord so stick it into that if block in
line 223 and the same thing around StopRecording. 

     return 0;
   }
   if (!recording_) {
@@ -256,11 +252,7 @@ int32_t AudioDeviceIOS::StartRecording() {
 int32_t AudioDeviceIOS::StopRecording() {
   LOGI() << "StopRecording";
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
-  if (!rec_is_initialized_) {
-    return 0;
-  }
-  if (!recording_) {
-    rec_is_initialized_ = false;
+  if (!rec_is_initialized_ || !recording_) {
     return 0;
   }
   if (!playing_) {