Replace QuicheStrCat() with absl::StrCat()

PiperOrigin-RevId: 345586710
Change-Id: I494392852e09fa7916d4430290096b37ae37a922
diff --git a/quic/core/quic_coalesced_packet.cc b/quic/core/quic_coalesced_packet.cc
index e266a76..4b4bc40 100644
--- a/quic/core/quic_coalesced_packet.cc
+++ b/quic/core/quic_coalesced_packet.cc
@@ -4,9 +4,9 @@
 
 #include "net/third_party/quiche/src/quic/core/quic_coalesced_packet.h"
 
+#include "absl/strings/str_cat.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_ptr_util.h"
-#include "net/third_party/quiche/src/common/platform/api/quiche_str_cat.h"
 
 namespace quic {
 
@@ -154,20 +154,19 @@
 
 std::string QuicCoalescedPacket::ToString(size_t serialized_length) const {
   // Total length and padding size.
-  std::string info = quiche::QuicheStrCat(
+  std::string info = absl::StrCat(
       "total_length: ", serialized_length,
       " padding_size: ", serialized_length - length_, " packets: {");
   // Packets' encryption levels.
   bool first_packet = true;
   for (int8_t i = ENCRYPTION_INITIAL; i < NUM_ENCRYPTION_LEVELS; ++i) {
     if (ContainsPacketOfEncryptionLevel(static_cast<EncryptionLevel>(i))) {
-      info = quiche::QuicheStrCat(
-          info, first_packet ? "" : ", ",
-          EncryptionLevelToString(static_cast<EncryptionLevel>(i)));
+      absl::StrAppend(&info, first_packet ? "" : ", ",
+                      EncryptionLevelToString(static_cast<EncryptionLevel>(i)));
       first_packet = false;
     }
   }
-  info = quiche::QuicheStrCat(info, "}");
+  absl::StrAppend(&info, "}");
   return info;
 }