Associate a scan mode with Physical Web listeners

components/physical_web/data_source/physical_web_data_source_impl.cc

 // Copyright 2016 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 "base/observer_list.h"
 #include "components/physical_web/data_source/physical_web_data_source.h"
 #include "components/physical_web/data_source/physical_web_data_source_impl.h"
 #include "components/physical_web/data_source/physical_web_listener.h"
 
 namespace physical_web {
 
 PhysicalWebDataSourceImpl::PhysicalWebDataSourceImpl() {}
 
 PhysicalWebDataSourceImpl::~PhysicalWebDataSourceImpl() {}
 
 void PhysicalWebDataSourceImpl::RegisterListener(
-    PhysicalWebListener* physical_web_listener) {
+    PhysicalWebListener* physical_web_listener, ScanMode scan_mode) {
   observer_list_.AddObserver(physical_web_listener);

[mattreynolds, 2017/03/21 19:02:56]

ObserverList says observers shouldn't be added more than once. Can you add a
check here to ensure we won't double-add when changing the scan mode?

[cco3, 2017/03/21 19:28:45]

O snap.

+  scan_modes_[physical_web_listener] = scan_mode;
 }
 
 void PhysicalWebDataSourceImpl::UnregisterListener(
     PhysicalWebListener* physical_web_listener) {
   observer_list_.RemoveObserver(physical_web_listener);
+  scan_modes_.erase(scan_modes_.find(physical_web_listener));
 }
 
 void PhysicalWebDataSourceImpl::NotifyOnFound(const GURL& url) {
   for (PhysicalWebListener& observer : observer_list_)
     observer.OnFound(url);
 }
 
 void PhysicalWebDataSourceImpl::NotifyOnLost(const GURL& url) {
   for (PhysicalWebListener& observer : observer_list_)
     observer.OnLost(url);
 }
 
 void PhysicalWebDataSourceImpl::NotifyOnDistanceChanged(
     const GURL& url,
     double distance_estimate) {
   for (PhysicalWebListener& observer : observer_list_)
     observer.OnDistanceChanged(url, distance_estimate);
 }
 
 }  // namespace physical_web