Create network change notifier.

webrtc/base/networkmonitor.cc

Index: webrtc/base/networkmonitor.cc
diff --git a/webrtc/base/networkmonitor.cc b/webrtc/base/networkmonitor.cc
new file mode 100644
index 0000000000000000000000000000000000000000..92bf0592b5fa3932b243968c93b3759c1e93365d
--- /dev/null
+++ b/webrtc/base/networkmonitor.cc
@@ -0,0 +1,62 @@
+/*
+ *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/base/networkmonitor.h"
+
+#include "webrtc/base/common.h"
+
+namespace {
+const uint32_t UPDATE_NETWORKS_MESSAGE = 1;
+
+// This is set by NetworkMonitorFactory::SetFactory and the caller of
+// NetworkMonitorFactory::SetFactory must be responsible for calling
+// ReleaseFactory to destroy the factory.
+rtc::NetworkMonitorFactory* network_monitor_factory = nullptr;
+}  // namespace
+
+namespace rtc {
+NetworkMonitorInterface::NetworkMonitorInterface() {}
+
+NetworkMonitorInterface::~NetworkMonitorInterface() {}
+
+NetworkMonitorBase::NetworkMonitorBase() : thread_(Thread::Current()) {}
+NetworkMonitorBase::~NetworkMonitorBase() {}
+
+void NetworkMonitorBase::OnNetworksChanged() {
+  LOG(LS_VERBOSE) << "Network change is received at the network monitor";
+  thread_->Post(this, UPDATE_NETWORKS_MESSAGE);
+}
+
+void NetworkMonitorBase::OnMessage(Message* msg) {
+  ASSERT(msg->message_id == UPDATE_NETWORKS_MESSAGE);
+  SignalNetworksChanged();
+}
+
+NetworkMonitorFactory::NetworkMonitorFactory() {}
+NetworkMonitorFactory::~NetworkMonitorFactory() {}
+
+void NetworkMonitorFactory::SetFactory(NetworkMonitorFactory* factory) {
+  if (network_monitor_factory != nullptr) {
+    delete network_monitor_factory;
+  }
+  network_monitor_factory = factory;
+}
+
+void NetworkMonitorFactory::ReleaseFactory(NetworkMonitorFactory* factory) {
+  if (factory == network_monitor_factory) {
+    SetFactory(nullptr);
+  }
+}
+
+NetworkMonitorFactory* NetworkMonitorFactory::GetFactory() {
+  return network_monitor_factory;
+}
+
+}  // namespace rtc