Add PlayoutVolumeChange RuntimeSetting.

Add a PlayoutVolumeChange RuntimeSetting. Trigger an echo path change when the playout volume is changed.

Bug: webrtc:10608
Change-Id: I1e736b93c1865d08c7d2582f6fe00216c1e1f72e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/135746
Reviewed-by: Per Åhgren <peah@webrtc.org>
Reviewed-by: Fredrik Hernqvist <fhernqvist@webrtc.org>
Commit-Queue: Fredrik Hernqvist <fhernqvist@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27913}

modules/audio_processing/include/audio_processing.h

@@ -392,6 +392,7 @@ class AudioProcessing : public rtc::RefCountInterface {
       kCapturePreGain,
       kCaptureCompressionGain,
       kCaptureFixedPostGain,
+      kPlayoutVolumeChange,
       kCustomRenderProcessingRuntimeSetting
     };
 
@@ -419,6 +420,10 @@ class AudioProcessing : public rtc::RefCountInterface {
       return {Type::kCaptureFixedPostGain, gain_db};
     }
 
+    static RuntimeSetting CreatePlayoutVolumeChange(int volume) {
+      return {Type::kPlayoutVolumeChange, volume};
+    }
+
     static RuntimeSetting CreateCustomRenderSetting(float payload) {
       return {Type::kCustomRenderProcessingRuntimeSetting, payload};
     }
@@ -426,13 +431,24 @@ class AudioProcessing : public rtc::RefCountInterface {
     Type type() const { return type_; }
     void GetFloat(float* value) const {
       RTC_DCHECK(value);
-      *value = value_;
+      *value = value_.float_value;
+    }
+    void GetInt(int* value) const {
+      RTC_DCHECK(value);
+      *value = value_.int_value;
     }
 
    private:
     RuntimeSetting(Type id, float value) : type_(id), value_(value) {}
+    RuntimeSetting(Type id, int value) : type_(id), value_(value) {}
     Type type_;
-    float value_;
+    union U {
+      U() {}
+      U(int value) : int_value(value) {}
+      U(float value) : float_value(value) {}
+      float float_value;
+      int int_value;
+    } value_;
   };
 
   ~AudioProcessing() override {}