Remove Http2StrCat, use QuicheStrCat instead.

gfe-relnote: n/a, no functional change.
PiperOrigin-RevId: 289866176
Change-Id: I87a1f30ed7efc348196d8666b719ba0a7de97f3f
diff --git a/http2/http2_structures.cc b/http2/http2_structures.cc
index 7b00db4..3558331 100644
--- a/http2/http2_structures.cc
+++ b/http2/http2_structures.cc
@@ -8,6 +8,7 @@
 #include <sstream>
 
 #include "net/third_party/quiche/src/http2/platform/api/http2_string_utils.h"
+#include "net/third_party/quiche/src/common/platform/api/quiche_str_cat.h"
 
 namespace http2 {
 
@@ -20,9 +21,9 @@
 }
 
 std::string Http2FrameHeader::ToString() const {
-  return Http2StrCat("length=", payload_length,
-                     ", type=", Http2FrameTypeToString(type),
-                     ", flags=", FlagsToString(), ", stream=", stream_id);
+  return quiche::QuicheStrCat(
+      "length=", payload_length, ", type=", Http2FrameTypeToString(type),
+      ", flags=", FlagsToString(), ", stream=", stream_id);
 }
 
 std::string Http2FrameHeader::FlagsToString() const {