Introduced new scheme for controlling the functionality inside the audio processing module

webrtc/modules/audio_processing/include/audio_processing.h

Index: webrtc/modules/audio_processing/include/audio_processing.h
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index 09e5d5be1cba9b20a8b8210c690c3c23e1dc7709..3fb5bef9e94f4a01ad59dc4234858f48f7e7c2ee 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -91,14 +91,6 @@ struct RefinedAdaptiveFilter {
   bool enabled;
 };
 
-// Enables the adaptive level controller.
-struct LevelControl {
-  LevelControl() : enabled(false) {}
-  explicit LevelControl(bool enabled) : enabled(enabled) {}
-  static const ConfigOptionID identifier = ConfigOptionID::kLevelControl;
-  bool enabled;
-};
-
 // Enables delay-agnostic echo cancellation. This feature relies on internally
 // estimated delays between the process and reverse streams, thus not relying
 // on reported system delays. This configuration only applies to
@@ -205,6 +197,14 @@ struct Intelligibility {
 // Usage example, omitting error checking:
 // AudioProcessing* apm = AudioProcessing::Create(0);
 //
+// AudioProcessing::Config config;
+// config.level_controller.enable = true;
+// bool config_ok = config.Validate();
+// RTC_DCHECK(config_ok);
+// if (config_ok {

[the sun, 2016/08/30 18:05:35]

No. The client should not be burdened with validating the struct. Just validate
internally in ApplyConfig() and return false if there's a problem (*before*
acting on anything in the struct).

[peah-webrtc, 2016/08/31 08:08:32]

Done.

+//   apm->ApplyConfig(config);
+// }
+//
 // apm->high_pass_filter()->Enable(true);
 //
 // apm->echo_cancellation()->enable_drift_compensation(false);
@@ -244,6 +244,25 @@ struct Intelligibility {
 //
 class AudioProcessing {
  public:
+  // The struct below constitutes the new parameter scheme for the
+  // audio processing functionality. It is being introduced gradually and
+  // until it is fully introduced, it is prone to change.
+  //
+  // The parameters and behavior of the audio processing module are controlled
+  // by changing the default values in the ApmConfig struct. It is possible

[the sun, 2016/08/30 18:05:35]

Update comment.

[peah-webrtc, 2016/08/31 08:08:31]

Done.

+  // to verify the specified parameters by calling the IsOk method for each
+  // substruct. The config are applied by passing the struct to the
+  // ApplyConfig method in the audio processing interface. The IsOk()
+  // method of the main struct calls all of the IsOk() methods in the
+  // substructs.
+  struct Config {
+    struct LevelController {
+      bool enabled = false;
+      bool Validate() const;

[the sun, 2016/08/30 18:05:35]

Again, the *knowledge* about a sane state for each config should live in the
actual processing module/component. The monolithic APM should know as little
detail as possible about each of the processors.

[peah-webrtc, 2016/08/31 08:08:32]

Done.

+    } level_controller;
+    bool Validate() const;
+  };
+
   // TODO(mgraczyk): Remove once all methods that use ChannelLayout are gone.
   enum ChannelLayout {
     kMono,
@@ -262,12 +281,16 @@ class AudioProcessing {
   // be one instance for every incoming stream.
   static AudioProcessing* Create();
   // Allows passing in an optional configuration at create-time.
-  static AudioProcessing* Create(const Config& config);
+  static AudioProcessing* Create(const webrtc::Config& config);
   // Only for testing.
-  static AudioProcessing* Create(const Config& config,
+  static AudioProcessing* Create(const webrtc::Config& config,
                                  NonlinearBeamformer* beamformer);
   virtual ~AudioProcessing() {}
 
+  // TODO(peah): This method is a temporary solution used to take control
+  // over the parameters in the audio processing module and is likely to change.
+  virtual bool ApplyConfig(const Config& config) = 0;

[the sun, 2016/08/30 18:05:35]

nit: Does it really belong before Initialize() ?

[peah-webrtc, 2016/08/31 08:08:31]

Good point! I'll put it by SetExtraOptions

Done.

+
   // Initializes internal states, while retaining all user settings. This
   // should be called before beginning to process a new audio stream. However,
   // it is not necessary to call before processing the first stream after
@@ -302,7 +325,7 @@ class AudioProcessing {
 
   // Pass down additional options which don't have explicit setters. This
   // ensures the options are applied immediately.
-  virtual void SetExtraOptions(const Config& config) = 0;
+  virtual void SetExtraOptions(const webrtc::Config& config) = 0;
 
   // TODO(ajm): Only intended for internal use. Make private and friend the
   // necessary classes?