arc: Reduce logspam when ARC is not enabled/available

components/arc/net/arc_net_host_impl.h

Index: components/arc/net/arc_net_host_impl.h
diff --git a/components/arc/net/arc_net_host_impl.h b/components/arc/net/arc_net_host_impl.h
index 58248c8faeb2786d8999c5a4177d46cd56b0aaa4..c0114a990024a8547b2b3010f019d244cec3cdc2 100644
--- a/components/arc/net/arc_net_host_impl.h
+++ b/components/arc/net/arc_net_host_impl.h
@@ -80,6 +80,7 @@ class ArcNetHostImpl : public ArcService,
 
   // Overridden from ArcBridgeService::InterfaceObserver<mojom::NetInstance>:
   void OnInstanceReady() override;
+  void OnInstanceClosed() override;
 
  private:
   void DefaultNetworkSuccessCallback(const std::string& service_path,
@@ -103,6 +104,10 @@ class ArcNetHostImpl : public ArcService,
       const std::string& error_name,
       std::unique_ptr<base::DictionaryValue> error_data);
 
+  // True if the chrome::NetworkStateHandler is currently being observed for
+  // state changes.
+  bool observing_network_state_ = false;
+
   std::string cached_service_path_;
   std::string cached_guid_;