Add a Physical Web data source

ios/chrome/common/physical_web/physical_web_scanner.h

 // 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.
 
 #ifndef IOS_CHROME_COMMON_PHYSICAL_WEB_PHYSICAL_WEB_SCANNER_H_
 #define IOS_CHROME_COMMON_PHYSICAL_WEB_PHYSICAL_WEB_SCANNER_H_
 
 #import <Foundation/Foundation.h>
 
-@class PhysicalWebDevice;
+#include <memory>
+
+namespace base {
+class ListValue;
+}
 
 @protocol PhysicalWebScannerDelegate;
 
 // This class will scan for physical web devices.
 
 @interface PhysicalWebScanner : NSObject
 
 // When networkRequest is NO, no network request will be sent.
 @property(nonatomic, assign) BOOL networkRequestEnabled;
 
@@ skipping 15 matching lines @@
 // It can happen when the bluetooth is turned off. In this case, scanning will
 // start as soon as the bluetooth is turned on.
 - (void)start;
 
 // Stop scanning.
 - (void)stop;
 
 // Returns a list of physical web devices (PhysicalWebDevice).
 - (NSArray*)devices;
 
+// Returns the metadata for all resolved physical web URLs. The returned value
+// will never be nil; if no metadata has been received then an empty list is
+// returned.
+- (std::unique_ptr<base::ListValue>)metadata;
+
 @end
 
 @protocol PhysicalWebScannerDelegate<NSObject>
 
 // This delegate method is called when the list of discovered devices is updated
 // by the scanner.
 - (void)scannerUpdatedDevices:(PhysicalWebScanner*)scanner;
 
 // This delegate method is called when the bluetooth status is updated.
 - (void)scannerBluetoothStatusUpdated:(PhysicalWebScanner*)scanner;
 
 @end
 
 #endif  // IOS_CHROME_COMMON_PHYSICAL_WEB_PHYSICAL_WEB_SCANNER_H_