Add base/parse_number.h to generalize number parsing done in //net.

net/base/host_port_pair.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/base/host_port_pair.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"

[mmenke, 2016/03/23 19:32:28]

Hrm...Guess we still need this for Uint to string.  There goes my idea of
banning this in net via DEPS.  Maybe a presubmit check, eventually?

[eroman, 2016/03/23 19:50:30]

Yeah, we can tackle this eventually.

There are a couple base::StringToInt() which I may not switch over -- in
particular ones being used to parse command-line flags. In this case it doesn't
seem harmful to be more permissive. Although it is inconsistent if we recognize
ports with a leading + from command line flag but nowhere else....

Either way, will think about once the bulk is addressed.

 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "net/base/ip_endpoint.h"
+#include "net/base/parse_number.h"
 #include "net/base/port_util.h"
 #include "url/gurl.h"
 
 namespace net {
 
 HostPortPair::HostPortPair() : port_(0) {}
 HostPortPair::HostPortPair(const std::string& in_host, uint16_t in_port)
     : host_(in_host), port_(in_port) {
 }
 
 // static
 HostPortPair HostPortPair::FromURL(const GURL& url) {
   return HostPortPair(url.HostNoBrackets(),
                       static_cast<uint16_t>(url.EffectiveIntPort()));
 }
 
 // static
 HostPortPair HostPortPair::FromIPEndPoint(const IPEndPoint& ipe) {
   return HostPortPair(ipe.ToStringWithoutPort(), ipe.port());
 }
 
 HostPortPair HostPortPair::FromString(const std::string& str) {
   std::vector<base::StringPiece> key_port = base::SplitStringPiece(
       str, ":", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
   if (key_port.size() != 2)
     return HostPortPair();
   int port;
-  if (!base::StringToInt(key_port[1], &port))
+  if (!ParseNonNegativeDecimalInt(key_port[1], &port))
     return HostPortPair();
   if (!IsPortValid(port))
     return HostPortPair();
   HostPortPair host_port_pair;
   host_port_pair.set_host(key_port[0].as_string());
   host_port_pair.set_port(static_cast<uint16_t>(port));
   return host_port_pair;
 }
 
 std::string HostPortPair::ToString() const {
@@ skipping 16 matching lines @@
   // Check to see if the host is an IPv6 address.  If so, added brackets.
   if (host_.find(':') != std::string::npos) {
     DCHECK_NE(host_[0], '[');
     return base::StringPrintf("[%s]", host_.c_str());
   }
 
   return host_;
 }
 
 }  // namespace net