Revert of Convert //net and //chromecast to std::unordered_*

net/dns/dns_hosts.h

 // 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.
 
 #ifndef NET_DNS_DNS_HOSTS_H_
 #define NET_DNS_DNS_HOSTS_H_
 
 #include <stddef.h>
 
 #include <map>
 #include <string>
-#include <unordered_map>
 #include <utility>
 #include <vector>
 
+#include "base/containers/hash_tables.h"
 #include "base/files/file_path.h"
-#include "base/strings/string_piece.h"
 #include "net/base/address_family.h"
 #include "net/base/ip_address.h"
 #include "net/base/net_export.h"
 
 namespace net {
+  typedef std::pair<std::string, AddressFamily> DnsHostsKey;
+};
 
-using DnsHostsKey = std::pair<std::string, AddressFamily>;
+namespace BASE_HASH_NAMESPACE {
 
-struct DnsHostsKeyHash {
-  std::size_t operator()(const DnsHostsKey& key) const {
+template<>
+struct hash<net::DnsHostsKey> {
+  std::size_t operator()(const net::DnsHostsKey& key) const {
     return base::StringPieceHash()(key.first) + key.second;
   }
 };
 
+}  // namespace BASE_HASH_NAMESPACE
+
+namespace net {
+
 // There are OS-specific variations in how commas in the hosts file behave.
 enum ParseHostsCommaMode {
   // Comma is treated as part of a hostname:
   // "127.0.0.1 foo,bar" parses as "foo,bar" mapping to "127.0.0.1".
   PARSE_HOSTS_COMMA_IS_TOKEN,
 
   // Comma is treated as a hostname separator:
   // "127.0.0.1 foo,bar" parses as "foo" and "bar" both mapping to "127.0.0.1".
   PARSE_HOSTS_COMMA_IS_WHITESPACE,
 };
 
 // Parsed results of a Hosts file.
 //
 // Although Hosts files map IP address to a list of domain names, for name
 // resolution the desired mapping direction is: domain name to IP address.
 // When parsing Hosts, we apply the "first hit" rule as Windows and glibc do.
 // With a Hosts file of:
 // 300.300.300.300 localhost # bad ip
 // 127.0.0.1 localhost
 // 10.0.0.1 localhost
 // The expected resolution of localhost is 127.0.0.1.
-using DnsHosts = std::unordered_map<DnsHostsKey, IPAddress, DnsHostsKeyHash>;
+#if !defined(OS_ANDROID)
+typedef base::hash_map<DnsHostsKey, IPAddress> DnsHosts;
+#else
+// Android's hash_map doesn't support ==, so fall back to map.  (Chromium on
+// Android doesn't use the built-in DNS resolver anyway, so it's irrelevant.)
+typedef std::map<DnsHostsKey, IPAddress> DnsHosts;
+#endif
 
 // Parses |contents| (as read from /etc/hosts or equivalent) and stores results
 // in |dns_hosts|. Invalid lines are ignored (as in most implementations).
 // Overrides the OS-specific default handling of commas, so unittests can test
 // both modes.
 void NET_EXPORT_PRIVATE ParseHostsWithCommaModeForTesting(
     const std::string& contents,
     DnsHosts* dns_hosts,
     ParseHostsCommaMode comma_mode);
 
 // Parses |contents| (as read from /etc/hosts or equivalent) and stores results
 // in |dns_hosts|. Invalid lines are ignored (as in most implementations).
 void NET_EXPORT_PRIVATE ParseHosts(const std::string& contents,
                                    DnsHosts* dns_hosts);
 
 // As above but reads the file pointed to by |path|.
 bool NET_EXPORT_PRIVATE ParseHostsFile(const base::FilePath& path,
                                        DnsHosts* dns_hosts);
 
 
 
 }  // namespace net
 
 #endif  // NET_DNS_DNS_HOSTS_H_