Delete the code used to record failed to serialize packet locations.

The bug is already fixed so the code is no longer needed.

PiperOrigin-RevId: 337917556
Change-Id: I6eb2a8cbb55ac707b8cbbaad76d86b2ccc4d51de
diff --git a/quic/core/quic_error_codes.cc b/quic/core/quic_error_codes.cc
index 75bbebd..a3529cf 100644
--- a/quic/core/quic_error_codes.cc
+++ b/quic/core/quic_error_codes.cc
@@ -7,7 +7,6 @@
 
 #include "third_party/boringssl/src/include/openssl/ssl.h"
 #include "net/third_party/quiche/src/quic/core/quic_error_codes.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_client_stats.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
 #include "net/third_party/quiche/src/common/platform/api/quiche_str_cat.h"
 
@@ -782,13 +781,6 @@
   return QUIC_STREAM_UNKNOWN_APPLICATION_ERROR_CODE;
 }
 
-void RecordFailToSerializePacketLocation(
-    QuicFailToSerializePacketLocation location) {
-  QUIC_CLIENT_HISTOGRAM_ENUM("QuicSession.FailToSerializePacketLocation",
-                             location, kMaxFailLocationValue,
-                             "The reason why a packet fails to serialize");
-}
-
 #undef RETURN_STRING_LITERAL  // undef for jumbo builds
 
 }  // namespace quic
diff --git a/quic/core/quic_error_codes.h b/quic/core/quic_error_codes.h
index 4771272..4df545e 100644
--- a/quic/core/quic_error_codes.h
+++ b/quic/core/quic_error_codes.h
@@ -615,36 +615,6 @@
   return "cause";
 }
 
-enum QuicFailToSerializePacketLocation {
-  kQuicFailToAppendPacketHeaderFastPath = 0,
-  kQuicFailToAppendTypeFastPath = 1,
-  kQuicFailToAppendStreamFrameFastPath = 2,
-  kQuicFailToAddPaddingFastPath = 3,
-  kQuicFailToWriteIetfLongHeaderLengthFastPath = 4,
-  kQuicFailToEncryptPacketFastPath = 5,
-  kQuicSerializePacketNonEmptyBuffer = 6,
-  kQuicMissingInitialKey = 7,
-  kQuicMissingHandshakeKey = 8,
-  kQuicMissingZeroRttKey = 9,
-  kQuicMissingOneRttKey = 10,
-  kQuicFailToBuildPacketWithPaddingInitial = 11,
-  kQuicFailToBuildPacketInitial = 12,
-  kQuicFailToBuildPacketWithPaddingHandshake = 13,
-  kQuicFailToBuildPacketHandshake = 14,
-  kQuicFailToBuildPacketWithPaddingZeroRtt = 15,
-  kQuicFailToBuildPacketZeroRtt = 16,
-  kQuicFailToBuildPacketWithPaddingOneRtt = 17,
-  kQuicFailToBuildPacketOneRtt = 18,
-  kQuicFailToEncryptInitial = 19,
-  kQuicFailToEncryptHandshake = 20,
-  kQuicFailToEncryptZeroRtt = 21,
-  kQuicFailToEncryptOneRtt = 22,
-  kMaxFailLocationValue = kQuicFailToEncryptOneRtt
-};
-
-QUIC_EXPORT_PRIVATE void RecordFailToSerializePacketLocation(
-    QuicFailToSerializePacketLocation location);
-
 }  // namespace quic
 
 #endif  // QUICHE_QUIC_CORE_QUIC_ERROR_CODES_H_
diff --git a/quic/core/quic_packet_creator.cc b/quic/core/quic_packet_creator.cc
index de6f77f..82d6fb5 100644
--- a/quic/core/quic_packet_creator.cc
+++ b/quic/core/quic_packet_creator.cc
@@ -607,7 +607,6 @@
   size_t length_field_offset = 0;
   if (!framer_->AppendPacketHeader(header, &writer, &length_field_offset)) {
     QUIC_BUG << "AppendPacketHeader failed";
-    RecordFailToSerializePacketLocation(kQuicFailToAppendPacketHeaderFastPath);
     return;
   }
 
@@ -649,12 +648,10 @@
   bool omit_frame_length = !needs_padding;
   if (!framer_->AppendTypeByte(QuicFrame(frame), omit_frame_length, &writer)) {
     QUIC_BUG << "AppendTypeByte failed";
-    RecordFailToSerializePacketLocation(kQuicFailToAppendTypeFastPath);
     return;
   }
   if (!framer_->AppendStreamFrame(frame, omit_frame_length, &writer)) {
     QUIC_BUG << "AppendStreamFrame failed";
-    RecordFailToSerializePacketLocation(kQuicFailToAppendStreamFrameFastPath);
     return;
   }
   if (needs_padding &&
@@ -662,14 +659,11 @@
       !writer.WritePaddingBytes(MinPlaintextPacketSize(framer_->version()) -
                                 plaintext_bytes_written)) {
     QUIC_BUG << "Unable to add padding bytes";
-    RecordFailToSerializePacketLocation(kQuicFailToAddPaddingFastPath);
     return;
   }
 
   if (!framer_->WriteIetfLongHeaderLength(header, &writer, length_field_offset,
                                           packet_.encryption_level)) {
-    RecordFailToSerializePacketLocation(
-        kQuicFailToWriteIetfLongHeaderLengthFastPath);
     return;
   }
 
@@ -684,7 +678,6 @@
       writer.length(), kMaxOutgoingPacketSize, encrypted_buffer);
   if (encrypted_length == 0) {
     QUIC_BUG << "Failed to encrypt packet number " << header.packet_number;
-    RecordFailToSerializePacketLocation(kQuicFailToEncryptPacketFastPath);
     return;
   }
   // TODO(ianswett): Optimize the storage so RetransmitableFrames can be
@@ -769,7 +762,6 @@
                                         size_t encrypted_buffer_len) {
   if (close_connection_on_serialization_failure_ &&
       packet_.encrypted_buffer != nullptr) {
-    RecordFailToSerializePacketLocation(kQuicSerializePacketNonEmptyBuffer);
     const std::string error_details =
         "Packet's encrypted buffer is not empty before serialization";
     QUIC_BUG << error_details;
@@ -813,22 +805,6 @@
              << QuicFramesToString(queued_frames_)
              << " at missing encryption_level " << packet_.encryption_level
              << " using " << framer_->version();
-    switch (packet_.encryption_level) {
-      case ENCRYPTION_INITIAL:
-        RecordFailToSerializePacketLocation(kQuicMissingInitialKey);
-        break;
-      case ENCRYPTION_HANDSHAKE:
-        RecordFailToSerializePacketLocation(kQuicMissingHandshakeKey);
-        break;
-      case ENCRYPTION_ZERO_RTT:
-        RecordFailToSerializePacketLocation(kQuicMissingZeroRttKey);
-        break;
-      case ENCRYPTION_FORWARD_SECURE:
-        RecordFailToSerializePacketLocation(kQuicMissingOneRttKey);
-        break;
-      default:
-        break;
-    }
     return false;
   }
 
@@ -847,42 +823,6 @@
              << latched_hard_max_packet_length_
              << ", max_packet_length_: " << max_packet_length_
              << ", header: " << header;
-    switch (packet_.encryption_level) {
-      case ENCRYPTION_INITIAL:
-        if (QuicUtils::ContainsFrameType(queued_frames_, PADDING_FRAME)) {
-          RecordFailToSerializePacketLocation(
-              kQuicFailToBuildPacketWithPaddingInitial);
-        } else {
-          RecordFailToSerializePacketLocation(kQuicFailToBuildPacketInitial);
-        }
-        break;
-      case ENCRYPTION_HANDSHAKE:
-        if (QuicUtils::ContainsFrameType(queued_frames_, PADDING_FRAME)) {
-          RecordFailToSerializePacketLocation(
-              kQuicFailToBuildPacketWithPaddingHandshake);
-        } else {
-          RecordFailToSerializePacketLocation(kQuicFailToBuildPacketHandshake);
-        }
-        break;
-      case ENCRYPTION_ZERO_RTT:
-        if (QuicUtils::ContainsFrameType(queued_frames_, PADDING_FRAME)) {
-          RecordFailToSerializePacketLocation(
-              kQuicFailToBuildPacketWithPaddingZeroRtt);
-        } else {
-          RecordFailToSerializePacketLocation(kQuicFailToBuildPacketZeroRtt);
-        }
-        break;
-      case ENCRYPTION_FORWARD_SECURE:
-        if (QuicUtils::ContainsFrameType(queued_frames_, PADDING_FRAME)) {
-          RecordFailToSerializePacketLocation(
-              kQuicFailToBuildPacketWithPaddingOneRtt);
-        } else {
-          RecordFailToSerializePacketLocation(kQuicFailToBuildPacketOneRtt);
-        }
-        break;
-      default:
-        break;
-    }
     return false;
   }
 
@@ -904,22 +844,6 @@
       encrypted_buffer_len, encrypted_buffer.buffer);
   if (encrypted_length == 0) {
     QUIC_BUG << "Failed to encrypt packet number " << packet_.packet_number;
-    switch (packet_.encryption_level) {
-      case ENCRYPTION_INITIAL:
-        RecordFailToSerializePacketLocation(kQuicFailToEncryptInitial);
-        break;
-      case ENCRYPTION_HANDSHAKE:
-        RecordFailToSerializePacketLocation(kQuicFailToEncryptHandshake);
-        break;
-      case ENCRYPTION_ZERO_RTT:
-        RecordFailToSerializePacketLocation(kQuicFailToEncryptZeroRtt);
-        break;
-      case ENCRYPTION_FORWARD_SECURE:
-        RecordFailToSerializePacketLocation(kQuicFailToEncryptOneRtt);
-        break;
-      default:
-        break;
-    }
     return false;
   }