Initialize data_buffer in PathChallenge and PathResponse frames to all 0s.

PiperOrigin-RevId: 384993215

quic/core/frames/quic_path_challenge_frame.h

diff --git a/quic/core/frames/quic_path_challenge_frame.h b/quic/core/frames/quic_path_challenge_frame.h
index 7c27a42..6966775 100644
--- a/quic/core/frames/quic_path_challenge_frame.h
+++ b/quic/core/frames/quic_path_challenge_frame.h
@@ -27,7 +27,7 @@
   // and non-zero when sent.
   QuicControlFrameId control_frame_id = kInvalidControlFrameId;
 
-  QuicPathFrameBuffer data_buffer;
+  QuicPathFrameBuffer data_buffer{};
 };
 }  // namespace quic
 

quic/core/frames/quic_path_response_frame.h

diff --git a/quic/core/frames/quic_path_response_frame.h b/quic/core/frames/quic_path_response_frame.h
index 6b43bda..a4a75be 100644
--- a/quic/core/frames/quic_path_response_frame.h
+++ b/quic/core/frames/quic_path_response_frame.h
@@ -27,7 +27,7 @@
   // and non-zero when sent.
   QuicControlFrameId control_frame_id = kInvalidControlFrameId;
 
-  QuicPathFrameBuffer data_buffer;
+  QuicPathFrameBuffer data_buffer{};
 };
 }  // namespace quic