Extend NetworkRoute with more info about local/remote endpoints

This patch extends the NetworkRoute struct with more information
about local/remote endpoints. It adds
- adapter type
- adapter id
- relay

(previously it was "only" network_id)

The patch leaves the {local/remote}_network_id fields
around and populated since downstream projects depend
on them. They will be removed once they have migrated.

OWNER: srte@ call/ test/
OWNER: asapersson@ video/
OWNER: hta@ p2p/ pc/ rtc_base/

BUG: webrtc:11434
Change-Id: I9bcec385b40d707db385fef40b2c7a315dd35dd0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/170628
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Jonas Oreland <jonaso@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30848}

rtc_base/network_constants.cc

@@ -0,0 +1,39 @@
+/*
+ *  Copyright 2020 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 "rtc_base/network_constants.h"
+
+#include "rtc_base/checks.h"
+
+namespace rtc {
+
+std::string AdapterTypeToString(AdapterType type) {
+  switch (type) {
+    case ADAPTER_TYPE_ANY:
+      return "Wildcard";
+    case ADAPTER_TYPE_UNKNOWN:
+      return "Unknown";
+    case ADAPTER_TYPE_ETHERNET:
+      return "Ethernet";
+    case ADAPTER_TYPE_WIFI:
+      return "Wifi";
+    case ADAPTER_TYPE_CELLULAR:
+      return "Cellular";
+    case ADAPTER_TYPE_VPN:
+      return "VPN";
+    case ADAPTER_TYPE_LOOPBACK:
+      return "Loopback";
+    default:
+      RTC_NOTREACHED() << "Invalid type " << type;
+      return std::string();
+  }
+}
+
+}  // namespace rtc