Add QuicStrCat.

net/quic/core/quic_multipath_sent_packet_manager.cc

Index: net/quic/core/quic_multipath_sent_packet_manager.cc
diff --git a/net/quic/core/quic_multipath_sent_packet_manager.cc b/net/quic/core/quic_multipath_sent_packet_manager.cc
index 45c880575a9c83863a4a4206e4ac17fda1e493cc..d6366ac0e09ae0729bae04d2de9a3f6e2d35e327 100644
--- a/net/quic/core/quic_multipath_sent_packet_manager.cc
+++ b/net/quic/core/quic_multipath_sent_packet_manager.cc
@@ -8,6 +8,7 @@
 
 #include "base/strings/string_number_conversions.h"
 #include "net/quic/core/quic_bug_tracker.h"
+#include "net/quic/platform/api/quic_str_cat.h"
 
 using std::string;
 
@@ -444,8 +445,9 @@ QuicMultipathSentPacketManager::MaybeGetSentPacketManagerForPath(
     QuicPathId path_id) const {
   if (path_id >= path_managers_info_.size() ||
       path_managers_info_[path_id].manager == nullptr) {
-    QUIC_BUG << "Sent packet manager of path: (" + base::IntToString(path_id) +
-                    ") must exist but does not.";
+    QUIC_BUG << QuicStrCat("Sent packet manager of path: (",
+                           static_cast<uint32_t>(path_id),
+                           ") must exist but does not.");
     return nullptr;
   }
 
@@ -461,8 +463,9 @@ QuicMultipathSentPacketManager::MaybeGetSentPacketManagerForActivePath(
     return nullptr;
   }
   if (path_managers_info_[path_id].state != ACTIVE) {
-    QUIC_BUG << "Sent packet manager of path: (" + base::IntToString(path_id) +
-                    ") must be active but is not.";
+    QUIC_BUG << QuicStrCat("Sent packet manager of path: (",
+                           static_cast<uint32_t>(path_id),
+                           ") must be active but is not.");
     return nullptr;
   }
 
@@ -495,17 +498,17 @@ QuicPathId QuicMultipathSentPacketManager::DetermineRetransmissionTimeoutPath()
 void QuicMultipathSentPacketManager::OnUnrecoverablePathError(
     QuicPathId path_id) {
   if (MaybeGetSentPacketManagerForPath(path_id) == nullptr) {
-    const string error_details = "Sent packet manager of path: (" +
-                                 base::IntToString(path_id) +
-                                 ") must exist but does not.";
+    const string error_details = QuicStrCat("Sent packet manager of path: (",
+                                            static_cast<uint32_t>(path_id),
+                                            ") must exist but does not.");
     delegate_->OnUnrecoverableError(QUIC_MULTIPATH_PATH_DOES_NOT_EXIST,
                                     error_details,
                                     ConnectionCloseSource::FROM_SELF);
     return;
   }
-  const string error_details = "Sent packet manager of path: (" +
-                               base::IntToString(path_id) +
-                               ") must be active but is not.";
+  const string error_details = QuicStrCat("Sent packet manager of path: (",
+                                          static_cast<uint32_t>(path_id),
+                                          ") must be active but is not.");
   delegate_->OnUnrecoverableError(QUIC_MULTIPATH_PATH_NOT_ACTIVE, error_details,
                                   ConnectionCloseSource::FROM_SELF);
 }