Adding platform support check for NetworkObserver

net/base/network_change_notifier.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/network_change_notifier.h"
 
 #include <limits>
 
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
@@ skipping 616 matching lines @@
     case SUBTYPE_NONE:
       return 0.0;
     case SUBTYPE_OTHER:
       return std::numeric_limits<double>::infinity();
   }
   NOTREACHED();
   return std::numeric_limits<double>::infinity();
 }
 
 // static
+bool NetworkChangeNotifier::AreNetworkHandlesSupported() {
+  if (g_network_change_notifier) {
+    return g_network_change_notifier->AreNetworkHandlesCurrentlySupported();
+  }
+  return false;
+}
+
+// static
 void NetworkChangeNotifier::GetConnectedNetworks(NetworkList* network_list) {
+  DCHECK(AreNetworkHandlesSupported());
   if (g_network_change_notifier) {
     g_network_change_notifier->GetCurrentConnectedNetworks(network_list);
   } else {
     network_list->clear();
   }
 }
 
 // static
 NetworkChangeNotifier::ConnectionType
 NetworkChangeNotifier::GetNetworkConnectionType(NetworkHandle network) {
+  DCHECK(AreNetworkHandlesSupported());
   return g_network_change_notifier
              ? g_network_change_notifier->GetCurrentNetworkConnectionType(
                    network)
              : CONNECTION_UNKNOWN;
 }
 
 // static
 NetworkChangeNotifier::NetworkHandle
 NetworkChangeNotifier::GetDefaultNetwork() {
+  DCHECK(AreNetworkHandlesSupported());
   return g_network_change_notifier
              ? g_network_change_notifier->GetCurrentDefaultNetwork()
              : kInvalidNetworkHandle;
 }
 
 // static
 void NetworkChangeNotifier::GetDnsConfig(DnsConfig* config) {
   if (!g_network_change_notifier) {
     *config = DnsConfig();
   } else {
@@ skipping 164 matching lines @@
 
 void NetworkChangeNotifier::AddMaxBandwidthObserver(
     MaxBandwidthObserver* observer) {
   if (g_network_change_notifier) {
     g_network_change_notifier->max_bandwidth_observer_list_->AddObserver(
         observer);
   }
 }
 
 void NetworkChangeNotifier::AddNetworkObserver(NetworkObserver* observer) {
+  DCHECK(AreNetworkHandlesSupported());
   if (g_network_change_notifier) {
     g_network_change_notifier->network_observer_list_->AddObserver(observer);
   }
 }
 
 void NetworkChangeNotifier::RemoveIPAddressObserver(
     IPAddressObserver* observer) {
   if (g_network_change_notifier) {
     g_network_change_notifier->ip_address_observer_list_->RemoveObserver(
         observer);
@@ skipping 25 matching lines @@
 
 void NetworkChangeNotifier::RemoveMaxBandwidthObserver(
     MaxBandwidthObserver* observer) {
   if (g_network_change_notifier) {
     g_network_change_notifier->max_bandwidth_observer_list_->RemoveObserver(
         observer);
   }
 }
 
 void NetworkChangeNotifier::RemoveNetworkObserver(NetworkObserver* observer) {
+  DCHECK(AreNetworkHandlesSupported());
   if (g_network_change_notifier) {
     g_network_change_notifier->network_observer_list_->RemoveObserver(observer);
   }
 }
 
 // static
 void NetworkChangeNotifier::NotifyObserversOfIPAddressChangeForTests() {
   if (g_network_change_notifier)
     g_network_change_notifier->NotifyObserversOfIPAddressChangeImpl();
 }
@@ skipping 75 matching lines @@
   // This default implementation conforms to the NetInfo V3 specification but
   // should be overridden to provide specific bandwidth data based on the
   // platform.
   *connection_type = GetCurrentConnectionType();
   *max_bandwidth_mbps =
       *connection_type == CONNECTION_NONE
           ? GetMaxBandwidthForConnectionSubtype(SUBTYPE_NONE)
           : GetMaxBandwidthForConnectionSubtype(SUBTYPE_UNKNOWN);
 }
 
+bool NetworkChangeNotifier::AreNetworkHandlesCurrentlySupported() const {
+  return false;
+}
+
 void NetworkChangeNotifier::GetCurrentConnectedNetworks(
     NetworkList* network_list) const {
   network_list->clear();
 }
 
 NetworkChangeNotifier::ConnectionType
 NetworkChangeNotifier::GetCurrentNetworkConnectionType(
     NetworkHandle network) const {
   return CONNECTION_UNKNOWN;
 }
@@ skipping 154 matching lines @@
 
 NetworkChangeNotifier::DisableForTest::~DisableForTest() {
   DCHECK(!g_network_change_notifier);
   g_network_change_notifier = network_change_notifier_;
 }
 
 void NetworkChangeNotifier::DNSObserver::OnInitialDNSConfigRead() {
 }
 
 }  // namespace net