arc: net: Listen on network configuration changes

Chrome listens on network configuration changes. The changes
are now triggered by DNS proxy addresses change. This is needed
for ARC to always have the correct DNS proxy addresses. Chrome
will pass the addresses to ARC on changes.

BUG=b:232882301
TEST=Observe that OnNetworkConfigurationChanged is called;

Change-Id: I1e2391d20fdad393ec8bf22f4d8234649427895e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3760110
Reviewed-by: Hugo Benichi <hugobenichi@google.com>
Commit-Queue: Jason Jeremy Iman <jasongustaman@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1028610}

ash/components/arc/net/arc_net_host_impl.cc

@@ -625,6 +625,9 @@ void ArcNetHostImpl::OnConnectionReady() {
         default_network->path(), base::BindOnce(&ArcVpnSuccessCallback),
         base::BindOnce(&ArcVpnErrorCallback, "disconnecting stale ARC VPN"));
   }
+
+  // Listen on network configuration changes.
+  ash::PatchPanelClient::Get()->AddObserver(this);
 }
 
 void ArcNetHostImpl::OnConnectionClosed() {
@@ -640,6 +643,12 @@ void ArcNetHostImpl::OnConnectionClosed() {
   observing_network_state_ = false;
 }
 
+void ArcNetHostImpl::NetworkConfigurationChanged() {
+  // Get patchpanel devices and update active networks.
+  ash::PatchPanelClient::Get()->GetDevices(base::BindOnce(
+      &ArcNetHostImpl::UpdateActiveNetworks, weak_factory_.GetWeakPtr()));
+}
+
 void ArcNetHostImpl::GetNetworks(mojom::GetNetworksRequestType type,
                                  GetNetworksCallback callback) {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);

ash/components/arc/net/arc_net_host_impl.h

@@ -19,6 +19,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "base/values.h"
+#include "chromeos/ash/components/dbus/patchpanel/patchpanel_client.h"
 #include "chromeos/ash/components/dbus/patchpanel/patchpanel_service.pb.h"
 #include "chromeos/ash/components/network/network_connection_observer.h"
 #include "chromeos/ash/components/network/network_profile_handler.h"
@@ -40,6 +41,7 @@ class ArcNetHostImpl : public KeyedService,
                        public ConnectionObserver<mojom::NetInstance>,
                        public chromeos::NetworkConnectionObserver,
                        public chromeos::NetworkStateHandlerObserver,
+                       public ash::PatchPanelClient::Observer,
                        public mojom::NetHost {
  public:
   // Returns singleton instance for the given BrowserContext,
@@ -215,6 +217,9 @@ class ArcNetHostImpl : public KeyedService,
   void ReceiveShillProperties(const std::string& service_path,
                               absl::optional<base::Value> shill_properties);
 
+  // PatchPanelClient::Observer implementation:
+  void NetworkConfigurationChanged() override;
+
   ArcBridgeService* const arc_bridge_service_;  // Owned by ArcServiceManager.
 
   // True if the chrome::NetworkStateHandler is currently being observed for