Add NetEqInput::PacketData::ToString method

webrtc/modules/audio_coding/neteq/tools/neteq_input.h

Index: webrtc/modules/audio_coding/neteq/tools/neteq_input.h
diff --git a/webrtc/modules/audio_coding/neteq/tools/neteq_input.h b/webrtc/modules/audio_coding/neteq/tools/neteq_input.h
index 3bb64a6ca0bd8bdf65bb7c188018cc1fce445659..a1e51a3045e7dfe2024e95db0a155ab5f007c876 100644
--- a/webrtc/modules/audio_coding/neteq/tools/neteq_input.h
+++ b/webrtc/modules/audio_coding/neteq/tools/neteq_input.h
@@ -13,6 +13,7 @@
 
 #include <algorithm>
 #include <memory>
+#include <string>
 
 #include "webrtc/base/buffer.h"
 #include "webrtc/base/optional.h"
@@ -27,6 +28,8 @@ namespace test {
 class NetEqInput {
  public:
   struct PacketData {
+    std::string ToString() const;
+
     RTPHeader header;
     rtc::Buffer payload;
     double time_ms;