ARC: Implement the startScan API to start scanning of WiFI APs.

components/arc/net/arc_net_host_impl.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/arc/net/arc_net_host_impl.h"
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "chromeos/network/network_handler.h"
 #include "chromeos/network/network_state_handler.h"
 #include "chromeos/network/network_util.h"
 #include "chromeos/network/onc/onc_utils.h"
 #include "components/arc/arc_bridge_service.h"
 #include "third_party/mojo/src/mojo/edk/embedder/embedder.h"
 
 namespace {
 
 const int kGetNetworksListLimit = 100;
 
 }  // namespace
 
 namespace arc {
 
+chromeos::NetworkStateHandler* GetStateHandler() {
+  return chromeos::NetworkHandler::Get()->network_state_handler();
+}
+
 ArcNetHostImpl::ArcNetHostImpl(ArcBridgeService* bridge_service)
     : ArcService(bridge_service), binding_(this) {
   arc_bridge_service()->AddObserver(this);
 }
 
 ArcNetHostImpl::~ArcNetHostImpl() {
   DCHECK(thread_checker_.CalledOnValidThread());
   arc_bridge_service()->RemoveObserver(this);
 }
 
@@ skipping 54 matching lines @@
     wc->bssid = tmp;
 
     data->networks.push_back(std::move(wc));
   }
 
   callback.Run(std::move(data));
 }
 
 void ArcNetHostImpl::GetWifiEnabledState(
     const GetWifiEnabledStateCallback& callback) {
-  chromeos::NetworkStateHandler* handler =
-      chromeos::NetworkHandler::Get()->network_state_handler();
-  bool is_enabled =
-      handler->IsTechnologyEnabled(chromeos::NetworkTypePattern::WiFi());
+  bool is_enabled = GetStateHandler()->IsTechnologyEnabled(
+      chromeos::NetworkTypePattern::WiFi());
 
   callback.Run(is_enabled);
 }
 
+void ArcNetHostImpl::StartScan() {
+  GetStateHandler()->RequestScan();

[dcheng, 2016/02/13 02:32:01]

How does ARC++ know when this is done?

[abhishekbh, 2016/02/16 22:00:05]

This API mimics the Android startScan API which is async. Another CL will be
sent out when the completion of this event and its results will be sent from
Host to ARC. 

+}
+
 }  // namespace arc