Avoid initial NetworkChangeNotifier OnDNSChanged() signal on Android

net/base/network_change_notifier.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_BASE_NETWORK_CHANGE_NOTIFIER_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 117 matching lines @@
 
    private:
     DISALLOW_COPY_AND_ASSIGN(ConnectionTypeObserver);
   };
 
   class NET_EXPORT DNSObserver {
    public:
     // Will be called when the DNS settings of the system may have changed.
     // Use GetDnsConfig to obtain the current settings.
     virtual void OnDNSChanged() = 0;
+    // Will be called when DNS settings of the system have been loaded.
+    // Use GetDnsConfig to obtain the current settings.
+    virtual void OnInitialDNSConfigRead();
 
    protected:
     DNSObserver() {}
     virtual ~DNSObserver() {}
 
    private:
     DISALLOW_COPY_AND_ASSIGN(DNSObserver);
   };
 
   class NET_EXPORT NetworkChangeObserver {
@@ skipping 150 matching lines @@
   static void RemoveConnectionTypeObserver(ConnectionTypeObserver* observer);
   static void RemoveDNSObserver(DNSObserver* observer);
   static void RemoveNetworkChangeObserver(NetworkChangeObserver* observer);
   static void RemoveMaxBandwidthObserver(MaxBandwidthObserver* observer);
 
   // Allow unit tests to trigger notifications.
   static void NotifyObserversOfIPAddressChangeForTests();
   static void NotifyObserversOfConnectionTypeChangeForTests(
       ConnectionType type);
   static void NotifyObserversOfNetworkChangeForTests(ConnectionType type);
+  static void NotifyObserversOfInitialDNSConfigReadForTests();
 
   // Enable or disable notifications from the host. After setting to true, be
   // sure to pump the RunLoop until idle to finish any preexisting
   // notifications.
   static void SetTestNotificationsOnly(bool test_only);
 
   // Return a string equivalent to |type|.
   static const char* ConnectionTypeToString(ConnectionType type);
 
   // Let the NetworkChangeNotifier know we received some data.
@@ skipping 75 matching lines @@
   // subtype. The mapping of connection type to maximum bandwidth is provided in
   // the NetInfo spec: http://w3c.github.io/netinfo/.
   static double GetMaxBandwidthForConnectionSubtype(ConnectionSubtype subtype);
 
   // Broadcasts a notification to all registered observers.  Note that this
   // happens asynchronously, even for observers on the current thread, even in
   // tests.
   static void NotifyObserversOfIPAddressChange();
   static void NotifyObserversOfConnectionTypeChange();
   static void NotifyObserversOfDNSChange();
+  static void NotifyObserversOfInitialDNSConfigRead();
   static void NotifyObserversOfNetworkChange(ConnectionType type);
   static void NotifyObserversOfMaxBandwidthChange(double max_bandwidth_mbps);
 
-  // Stores |config| in NetworkState and notifies observers.
+  // Stores |config| in NetworkState and notifies OnDNSChanged observers.
   static void SetDnsConfig(const DnsConfig& config);
+  // Stores |config| in NetworkState and notifies OnInitialDNSConfigRead
+  // observers.
+  static void SetInitialDnsConfig(const DnsConfig& config);
 
  private:
   friend class HostResolverImplDnsTest;
   friend class NetworkChangeNotifierAndroidTest;
   friend class NetworkChangeNotifierLinuxTest;
   friend class NetworkChangeNotifierWinTest;
 
   class NetworkState;
   class NetworkChangeCalculator;
 
   void NotifyObserversOfIPAddressChangeImpl();
   void NotifyObserversOfConnectionTypeChangeImpl(ConnectionType type);
   void NotifyObserversOfDNSChangeImpl();
+  void NotifyObserversOfInitialDNSConfigReadImpl();
   void NotifyObserversOfNetworkChangeImpl(ConnectionType type);
   void NotifyObserversOfMaxBandwidthChangeImpl(double max_bandwidth_mbps);
 
   const scoped_refptr<ObserverListThreadSafe<IPAddressObserver>>
       ip_address_observer_list_;
   const scoped_refptr<ObserverListThreadSafe<ConnectionTypeObserver>>
       connection_type_observer_list_;
   const scoped_refptr<ObserverListThreadSafe<DNSObserver>>
       resolver_state_observer_list_;
   const scoped_refptr<ObserverListThreadSafe<NetworkChangeObserver>>
@@ skipping 12 matching lines @@
 
   // Set true to disable non-test notifications (to prevent flakes in tests).
   bool test_notifications_only_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifier);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_H_