Start the Physical Web scanner on Chrome start

ios/chrome/browser/physical_web/start_physical_web_discovery.h

Index: ios/chrome/browser/physical_web/start_physical_web_discovery.h
diff --git a/ios/chrome/browser/physical_web/start_physical_web_discovery.h b/ios/chrome/browser/physical_web/start_physical_web_discovery.h
new file mode 100644
index 0000000000000000000000000000000000000000..71704ac5bcdbb8eadd3bd94a2fe5e989aab7682d
--- /dev/null
+++ b/ios/chrome/browser/physical_web/start_physical_web_discovery.h
@@ -0,0 +1,14 @@
+// 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"
+
+// Checks the environment and starts Physical Web discovery if the required
+// conditions are met.
+void StartPhysicalWebDiscovery(PrefService* pref_service);
+
+#endif  // IOS_CHROME_BROWSER_PHYSICAL_WEB_START_PHYSICAL_WEB_DISCOVERY_H_