Avoid initial NetworkChangeNotifier OnDNSChanged() signal on Android

net/dns/dns_config_service_posix.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_CONFIG_SERVICE_POSIX_H_
 #define NET_DNS_DNS_CONFIG_SERVICE_POSIX_H_
 
 #if !defined(OS_ANDROID)
 #include <sys/types.h>
 #include <netinet/in.h>
 #include <resolv.h>
 #endif
 
 #include "base/compiler_specific.h"
+#include "base/files/file_path.h"
 #include "net/base/net_export.h"
+#include "net/base/network_change_notifier.h"
 #include "net/dns/dns_config_service.h"
 
+namespace base {
+class Time;
+}  // namespace base
+
 namespace net {
 
 // Use DnsConfigService::CreateSystemService to use it outside of tests.
 namespace internal {
 
+// Note: On Android NetworkChangeNotifier::OnNetworkChanged() signals must be
+// passed in via calls to OnNetworkChanged().
 class NET_EXPORT_PRIVATE DnsConfigServicePosix : public DnsConfigService {
  public:
   DnsConfigServicePosix();
   ~DnsConfigServicePosix() override;
 
+#if defined(OS_ANDROID)
+  // Returns whether the DnsConfigServicePosix witnessed a DNS configuration
+  // change since |since_time|.  Requires that callers have started listening
+  // for NetworkChangeNotifier::OnNetworkChanged() signals, and passing them in
+  // via OnNetworkChanged(), prior to |since_time|.
+  bool SeenChangeSince(const base::Time& since_time) const;
+  // NetworkChangeNotifier::OnNetworkChanged() signals must be passed
+  // in via calls to OnNetworkChanged().  Allowing external sources of
+  // this signal allows users of DnsConfigServicePosix to start watching for
+  // NetworkChangeNotifier::OnNetworkChanged() signals prior to the
+  // DnsConfigServicePosix even being created.
+  void OnNetworkChanged(NetworkChangeNotifier::ConnectionType type);
+#endif
+
+  void SetDnsConfigForTesting(const DnsConfig* dns_config);
+
  protected:
   // DnsConfigService:
   void ReadNow() override;
   bool StartWatching() override;
 
  private:
+  friend class DnsConfigServicePosixTest;
   class Watcher;
   class ConfigReader;
   class HostsReader;
 
   void OnConfigChanged(bool succeeded);
   void OnHostsChanged(bool succeeded);
 
   scoped_ptr<Watcher> watcher_;
+  // Allow a mock hosts file for testing purposes.
+  const base::FilePath::CharType* file_path_hosts_;
+  // Allow a mock DNS server for testing purposes.
+  const DnsConfig* dns_config_for_testing_;
   scoped_refptr<ConfigReader> config_reader_;
   scoped_refptr<HostsReader> hosts_reader_;
+#if defined(OS_ANDROID)
+  // Has DnsConfigWatcher detected any config chagnes yet?
+  bool seen_config_change_;
+#endif
 
   DISALLOW_COPY_AND_ASSIGN(DnsConfigServicePosix);
 };
 
 enum ConfigParsePosixResult {
   CONFIG_PARSE_POSIX_OK = 0,
   CONFIG_PARSE_POSIX_RES_INIT_FAILED,
   CONFIG_PARSE_POSIX_RES_INIT_UNSET,
   CONFIG_PARSE_POSIX_BAD_ADDRESS,
   CONFIG_PARSE_POSIX_BAD_EXT_STRUCT,
   CONFIG_PARSE_POSIX_NULL_ADDRESS,
   CONFIG_PARSE_POSIX_NO_NAMESERVERS,
   CONFIG_PARSE_POSIX_MISSING_OPTIONS,
   CONFIG_PARSE_POSIX_UNHANDLED_OPTIONS,
   CONFIG_PARSE_POSIX_NO_DNSINFO,
   CONFIG_PARSE_POSIX_MAX  // Bounding values for enumeration.
 };
 
 #if !defined(OS_ANDROID)
 // Fills in |dns_config| from |res|.
 ConfigParsePosixResult NET_EXPORT_PRIVATE ConvertResStateToDnsConfig(
     const struct __res_state& res, DnsConfig* dns_config);
 #endif
 
 }  // namespace internal
 
 }  // namespace net
 
 #endif  // NET_DNS_DNS_CONFIG_SERVICE_POSIX_H_