Fix busy loop in FakeAudioDeviceModule.

webrtc/modules/audio_device/include/fake_audio_device.h

Index: webrtc/modules/audio_device/include/fake_audio_device.h
diff --git a/webrtc/modules/audio_device/include/fake_audio_device.h b/webrtc/modules/audio_device/include/fake_audio_device.h
index a28ad8646436eaaec4f2a7bb016c927e5cc3d7ab..1797dd5e8db9b5cc978075a62f907e257324f8d2 100644
--- a/webrtc/modules/audio_device/include/fake_audio_device.h
+++ b/webrtc/modules/audio_device/include/fake_audio_device.h
@@ -41,8 +41,20 @@ class FakeAudioDeviceModule : public AudioDeviceModule {
   virtual int32_t SetStereoRecording(bool enable) { return 0; }
   virtual int32_t SetAGC(bool enable) { return 0; }
   virtual int32_t StopRecording() { return 0; }
-  virtual int64_t TimeUntilNextProcess() { return 0; }
-  virtual void Process() {}
+
+  // If the subclass doesn't override the ProcessThread implementation,
+  // we'll fall back on an implementation that doesn't eat too much CPU.
+  virtual int64_t TimeUntilNextProcess() {
+    if (turn_off_module_callbacks_)

[the sun, 2017/02/25 20:01:07]

return time_until_next_process_;

+      return 7 * 24 * 60 * 60 * 1000;  // call me next week.
+    uses_default_module_implementation_ = true;
+    return 10;
+  }
+
+  virtual void Process() {
+    turn_off_module_callbacks_ = uses_default_module_implementation_;

[the sun, 2017/02/25 20:01:07]

// After first call to Process(), we wait a long time to avoid hogging CPU.
time_until_next_process_ = 7 * 24 * 60 * 60 * 1000;  // call me next week.

+  }
+
   virtual int32_t Terminate() { return 0; }
 
   virtual int32_t ActiveAudioLayer(AudioLayer* audioLayer) const { return 0; }
@@ -167,6 +179,10 @@ class FakeAudioDeviceModule : public AudioDeviceModule {
     return -1;
   }
 #endif  // WEBRTC_IOS
+
+ private:
+  bool uses_default_module_implementation_ = false;

[the sun, 2017/02/25 20:01:07]

int64_t time_until_next_process_ = 10;

+  bool turn_off_module_callbacks_ = false;
 };
 
 }  // namespace webrtc