Add native API for creating AndroidNetworkMonitorFactory.

Moves AndroidNetworkMonitor out of pc folder. Even clients not using
PeerConnection seem to be using it and it doesn't have any dependencies
to the PeerConnection API.

Bug: webrtc:8769
Change-Id: I2bdeff9f5c9925e13388fbc77aa9b264a7583548
Reviewed-on: https://webrtc-review.googlesource.com/53260
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22051}

sdk/android/native_api/base/networkmonitor.cc

@@ -0,0 +1,25 @@
+/*
+ *  Copyright 2018 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 "sdk/android/native_api/base/networkmonitor.h"
+
+#include <memory>
+
+#include "rtc_base/ptr_util.h"
+#include "sdk/android/src/jni/androidnetworkmonitor.h"
+
+namespace webrtc {
+
+std::unique_ptr<rtc::NetworkMonitorFactory>
+CreateAndroidNetworkMonitorFactory() {
+  return rtc::MakeUnique<jni::AndroidNetworkMonitorFactory>();
+}
+
+}  // namespace webrtc

sdk/android/native_api/base/networkmonitor.h

@@ -0,0 +1,29 @@
+/*
+ *  Copyright 2018 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.
+ */
+
+#ifndef SDK_ANDROID_NATIVE_API_BASE_NETWORKMONITOR_H_
+#define SDK_ANDROID_NATIVE_API_BASE_NETWORKMONITOR_H_
+
+#include <memory>
+
+#include "rtc_base/networkmonitor.h"
+
+namespace webrtc {
+
+// Creates an Android-specific network monitor, which is capable of detecting
+// network changes as soon as they occur, requesting a cellular interface
+// (dependent on permissions), and binding sockets to network interfaces (more
+// reliable than binding to IP addresses on Android).
+std::unique_ptr<rtc::NetworkMonitorFactory>
+CreateAndroidNetworkMonitorFactory();
+
+}  // namespace webrtc
+
+#endif  // SDK_ANDROID_NATIVE_API_BASE_NETWORKMONITOR_H_