Factor out StringAppendF into spdy/platform/.

net/spdy/spdy_alt_svc_wire_format.cc

 // Copyright (c) 2015 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/spdy/spdy_alt_svc_wire_format.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
 #include "base/logging.h"
 #include "base/strings/string_util.h"

[diannahu, 2017/03/29 15:42:57]

Can this be removed?

[Bence, 2017/03/29 16:56:18]

Unfortunately not: it is needed for base::IsHexDigit() and base:HexDigitToInt().

[xunjieli, 2017/03/29 17:43:48]

I am still concerned about this approach. Does having the two repos exactly in
sync justify this code churn? Here, we aren't able to get rid of the direct
dependency of base/strings/string_util.h because there are two more methods need
to be migrated. I am concerned that we might introduce subtle bugs this way and
might cause more headaches down the road.

A good enough approach that works for me is to have the merge script to do a
find-and-replace. 

I know QUIC team is doing the same. Is there a discussion thread somewhere?

-#include "base/strings/stringprintf.h"
+#include "net/spdy/platform/api/spdy_string_utils.h"
 
 namespace net {
 
 namespace {
 
 template <class T>
 bool ParsePositiveIntegerImpl(SpdyStringPiece::const_iterator c,
                               SpdyStringPiece::const_iterator end,
                               T* value) {
   *value = 0;
@@ skipping 209 matching lines @@
       }
     }
     value.push_back('=');
     value.push_back('"');
     for (char c : altsvc.host) {
       if (c == '"' || c == '\\') {
         value.push_back('\\');
       }
       value.push_back(c);
     }
-    base::StringAppendF(&value, ":%d\"", altsvc.port);
+    SpdyStringAppendF(&value, ":%d\"", altsvc.port);
     if (altsvc.max_age != 86400) {
-      base::StringAppendF(&value, "; ma=%d", altsvc.max_age);
+      SpdyStringAppendF(&value, "; ma=%d", altsvc.max_age);
     }
     if (!altsvc.version.empty()) {
       value.append("; v=\"");
       for (VersionVector::const_iterator it = altsvc.version.begin();
            it != altsvc.version.end(); ++it) {
         if (it != altsvc.version.begin()) {
           value.append(",");
         }
-        base::StringAppendF(&value, "%d", *it);
+        SpdyStringAppendF(&value, "%d", *it);
       }
       value.append("\"");
     }
   }
   return value;
 }
 
 // static
 void SpdyAltSvcWireFormat::SkipWhiteSpace(SpdyStringPiece::const_iterator* c,
                                           SpdyStringPiece::const_iterator end) {
@@ skipping 88 matching lines @@
 
 // static
 bool SpdyAltSvcWireFormat::ParsePositiveInteger32(
     SpdyStringPiece::const_iterator c,
     SpdyStringPiece::const_iterator end,
     uint32_t* value) {
   return ParsePositiveIntegerImpl<uint32_t>(c, end, value);
 }
 
 }  // namespace net