Add QuicStrCat.

net/quic/core/quic_session_test.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/core/quic_session.h"
 
 #include <set>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
@@ skipping 903 matching lines @@
   EXPECT_FALSE(headers_stream->flow_controller()->IsBlocked());
   EXPECT_FALSE(session_.IsConnectionFlowControlBlocked());
   EXPECT_FALSE(session_.IsStreamFlowControlBlocked());
   QuicStreamId stream_id = 5;
   // Write until the header stream is flow control blocked.
   EXPECT_CALL(*connection_, SendBlocked(kHeadersStreamId));
   SpdyHeaderBlock headers;
   while (!headers_stream->flow_controller()->IsBlocked() && stream_id < 2000) {
     EXPECT_FALSE(session_.IsConnectionFlowControlBlocked());
     EXPECT_FALSE(session_.IsStreamFlowControlBlocked());
-    headers["header"] = base::Uint64ToString(base::RandUint64()) +
-                        base::Uint64ToString(base::RandUint64()) +
-                        base::Uint64ToString(base::RandUint64());
+    headers["header"] = QuicStrCat("", base::RandUint64(), base::RandUint64(),
+                                   base::RandUint64());
     headers_stream->WriteHeaders(stream_id, headers.Clone(), true, 0, nullptr);
     stream_id += 2;
   }
   // Write once more to ensure that the headers stream has buffered data. The
   // random headers may have exactly filled the flow control window.
   headers_stream->WriteHeaders(stream_id, std::move(headers), true, 0, nullptr);
   EXPECT_TRUE(headers_stream->HasBufferedData());
 
   EXPECT_TRUE(headers_stream->flow_controller()->IsBlocked());
   EXPECT_FALSE(crypto_stream->flow_controller()->IsBlocked());
@@ skipping 378 matching lines @@
   if (version() <= QUIC_VERSION_35) {
     EXPECT_FALSE(session_.force_hol_blocking());
   } else {
     EXPECT_TRUE(session_.force_hol_blocking());
   }
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net