Refactor network_monitor_java out of peerconnection_java.

This is continuation work from https://webrtc-review.googlesource.com/c/src/+/229322

Bug: webrtc:13117
Change-Id: I649147ab8f978926c2e00ad45b388fb400d6545f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/230080
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Commit-Queue: Tim Na <natim@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34909}

sdk/android/BUILD.gn

@@ -530,6 +530,24 @@ if (is_android) {
       "//third_party/androidx:androidx_annotation_annotation_java",
     ]
   }
+
+  rtc_android_library("network_monitor_java") {
+    visibility = [ "*" ]
+    sources = [
+      "api/org/webrtc/NetworkChangeDetector.java",
+      "api/org/webrtc/NetworkChangeDetectorFactory.java",
+      "api/org/webrtc/NetworkMonitor.java",
+      "api/org/webrtc/NetworkMonitorAutoDetect.java",
+    ]
+    deps = [
+      ":base_java",
+      ":logging_java",
+      "//rtc_base:base_java",
+      "//third_party/android_deps:com_android_support_support_annotations_java",
+      "//third_party/androidx:androidx_annotation_annotation_java",
+    ]
+    srcjar_deps = [ "//rtc_base:network_monitor_enums" ]
+  }
 }
 
 if (current_os == "linux" || is_android) {

sdk/android/api/org/webrtc/NetworkMonitorAutoDetect.java

@@ -584,8 +584,7 @@ public class NetworkMonitorAutoDetect extends BroadcastReceiver implements Netwo
     wifiSSID = getWifiSSID(networkState);
     intentFilter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
 
-    if (PeerConnectionFactory.fieldTrialsFindFullName("IncludeWifiDirect").equals("Enabled")
-        || includeWifiDirect) {
+    if (includeWifiDirect) {
       wifiDirectManagerDelegate = new WifiDirectManagerDelegate(observer, context);
     }