Avoid initial NetworkChangeNotifier OnDNSChanged() signal on Android

net/dns/dns_config_service_posix.h

Index: net/dns/dns_config_service_posix.h
diff --git a/net/dns/dns_config_service_posix.h b/net/dns/dns_config_service_posix.h
index 349c82d1b8b543b4e3abfac8b25d20611e5a8378..7e266ba0460cc792f6b256dce50bb9ecdd1a07ad 100644
--- a/net/dns/dns_config_service_posix.h
+++ b/net/dns/dns_config_service_posix.h
@@ -12,25 +12,50 @@
 #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;
@@ -39,8 +64,16 @@ class NET_EXPORT_PRIVATE DnsConfigServicePosix : public DnsConfigService {
   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);
 };