dumpsys: add --json option to media.audio_flinger.

Currently only extracting audio performance data.

Test: dumpsys media.audio_flinger --json
Bug: 68148948
Change-Id: If207e7e20683dcf8d8d5874417cd7466c78a5df0
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 0276cad..fb83d75 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -23,6 +23,8 @@
 #include <mutex>
 #include <deque>
 #include <map>
+#include <memory>
+#include <string>
 #include <vector>
 #include <stdint.h>
 #include <sys/types.h>
@@ -111,6 +113,7 @@
     static const char* getServiceName() ANDROID_API { return "media.audio_flinger"; }
 
     virtual     status_t    dump(int fd, const Vector<String16>& args);
+                std::string getJsonString();
 
     // IAudioFlinger interface, in binder opcode order
     virtual sp<IAudioTrack> createTrack(const CreateTrackInput& input,