Experimental patch for delaying mic permission dialog in AppRTCMobile

webrtc/modules/audio_device/ios/voice_processing_audio_unit.mm

 /*
  *  Copyright 2016 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.
  */
 
@@ skipping 66 matching lines @@
 }
 
 VoiceProcessingAudioUnit::~VoiceProcessingAudioUnit() {
   DisposeAudioUnit();
 }
 
 const UInt32 VoiceProcessingAudioUnit::kBytesPerSample = 2;
 
 bool VoiceProcessingAudioUnit::Init() {
   RTC_DCHECK_EQ(state_, kInitRequired);
+  RTCLog(@"Init");
 
   // Create an audio component description to identify the Voice Processing
   // I/O audio unit.
   AudioComponentDescription vpio_unit_description;
   vpio_unit_description.componentType = kAudioUnitType_Output;
   vpio_unit_description.componentSubType = kAudioUnitSubType_VoiceProcessingIO;
   vpio_unit_description.componentManufacturer = kAudioUnitManufacturer_Apple;
   vpio_unit_description.componentFlags = 0;
   vpio_unit_description.componentFlagsMask = 0;
 
   // Obtain an audio unit instance given the description.
   AudioComponent found_vpio_unit_ref =
       AudioComponentFindNext(nullptr, &vpio_unit_description);
 
   // Create a Voice Processing IO audio unit.
   OSStatus result = noErr;
   result = AudioComponentInstanceNew(found_vpio_unit_ref, &vpio_unit_);
   if (result != noErr) {
     vpio_unit_ = nullptr;
     RTCLogError(@"AudioComponentInstanceNew failed. Error=%ld.", (long)result);
     return false;
   }
 
-  // Enable input on the input scope of the input element.
-  UInt32 enable_input = 1;
-  result = AudioUnitSetProperty(vpio_unit_, kAudioOutputUnitProperty_EnableIO,
-                                kAudioUnitScope_Input, kInputBus, &enable_input,
-                                sizeof(enable_input));
-  if (result != noErr) {
-    DisposeAudioUnit();
-    RTCLogError(@"Failed to enable input on input scope of input element. "
-                 "Error=%ld.",
-                (long)result);
-    return false;
-  }
-
   // Enable output on the output scope of the output element.
   UInt32 enable_output = 1;
   result = AudioUnitSetProperty(vpio_unit_, kAudioOutputUnitProperty_EnableIO,
                                 kAudioUnitScope_Output, kOutputBus,
                                 &enable_output, sizeof(enable_output));
   if (result != noErr) {
     DisposeAudioUnit();
     RTCLogError(@"Failed to enable output on output scope of output element. "
                  "Error=%ld.",
                 (long)result);
@@ skipping 54 matching lines @@
 
 VoiceProcessingAudioUnit::State VoiceProcessingAudioUnit::GetState() const {
   return state_;
 }
 
 bool VoiceProcessingAudioUnit::Initialize(Float64 sample_rate) {
   RTC_DCHECK_GE(state_, kUninitialized);
   RTCLog(@"Initializing audio unit with sample rate: %f", sample_rate);
 
   OSStatus result = noErr;
+
+  // Enable input on the input scope of the input element.
+  UInt32 enable_input = 1;
+  result = AudioUnitSetProperty(vpio_unit_, kAudioOutputUnitProperty_EnableIO,
+                                kAudioUnitScope_Input, kInputBus, &enable_input,
+                                sizeof(enable_input));
+  if (result != noErr) {
+    DisposeAudioUnit();
+    RTCLogError(@"Failed to enable input on input scope of input element. "
+                 "Error=%ld.",
+                (long)result);
+    return false;
+  }
+
   AudioStreamBasicDescription format = GetFormat(sample_rate);
   UInt32 size = sizeof(format);
 #if !defined(NDEBUG)
   LogStreamDescription(format);
 #endif
 
   // Set the format on the output scope of the input element/bus.
   result =
       AudioUnitSetProperty(vpio_unit_, kAudioUnitProperty_StreamFormat,
                            kAudioUnitScope_Output, kInputBus, &format, size);
@@ skipping 241 matching lines @@
     OSStatus result = AudioComponentInstanceDispose(vpio_unit_);
     if (result != noErr) {
       RTCLogError(@"AudioComponentInstanceDispose failed. Error=%ld.",
                   (long)result);
     }
     vpio_unit_ = nullptr;
   }
 }
 
 }  // namespace webrtc