Modify StartPhysicalWebDiscovery to take an ios::ChromeBrowserState param

ios/chrome/browser/physical_web/start_physical_web_discovery.h

 // 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.
 
 #ifndef IOS_CHROME_BROWSER_PHYSICAL_WEB_START_PHYSICAL_WEB_DISCOVERY_H_
 #define IOS_CHROME_BROWSER_PHYSICAL_WEB_START_PHYSICAL_WEB_DISCOVERY_H_
 
 #include "components/prefs/pref_service.h"
 
+namespace ios {
+class ChromeBrowserState;
+}
+
 // Checks the environment and starts Physical Web discovery if the required
 // conditions are met.
+// Deprecated, use the version below that takes an ios::ChromeBrowserState.
+// TODO(mattreynolds): remove once downstream users have been switched to the
+// new method.
 void StartPhysicalWebDiscovery(PrefService* pref_service, bool is_incognito);
 
+// Checks the environment and starts Physical Web discovery if the required
+// conditions are met.
+void StartPhysicalWebDiscovery(PrefService* pref_service,
+                               ios::ChromeBrowserState* browser_state);
+
 #endif  // IOS_CHROME_BROWSER_PHYSICAL_WEB_START_PHYSICAL_WEB_DISCOVERY_H_