Remove GetMetadata from PhysicalWebDataSource and PhysicalWebScanner

ios/chrome/browser/physical_web/ios_chrome_physical_web_data_source.mm

 // 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.
 
 #import "ios/chrome/browser/physical_web/ios_chrome_physical_web_data_source.h"
 
 #include "base/memory/ptr_util.h"
-#include "base/values.h"
 #import "ios/chrome/browser/physical_web/physical_web_initial_state_recorder.h"
 #import "ios/chrome/common/physical_web/physical_web_scanner.h"
 
 IOSChromePhysicalWebDataSource::IOSChromePhysicalWebDataSource(
     PrefService* pref_service) {
   initialStateRecorder_.reset([[PhysicalWebInitialStateRecorder alloc]
       initWithPrefService:pref_service]);
   [initialStateRecorder_ collectAndRecordState];
 }
 
@@ skipping 19 matching lines @@
   [scanner_ setOnLostDetectionEnabled:YES];
   [scanner_ setNetworkRequestEnabled:network_request_enabled];
   [scanner_ start];
 }
 
 void IOSChromePhysicalWebDataSource::StopDiscovery() {
   [scanner_ stop];
   scanner_.reset();
 }
 
-std::unique_ptr<base::ListValue> IOSChromePhysicalWebDataSource::GetMetadata() {
-  if (!scanner_) {
-    return base::MakeUnique<base::ListValue>();
-  }
-  return [scanner_ metadata];
-}
-
 std::unique_ptr<physical_web::MetadataList>
 IOSChromePhysicalWebDataSource::GetMetadataList() {
   if (!scanner_) {
     return base::MakeUnique<physical_web::MetadataList>();
   }
   return [scanner_ metadataList];
 }
 
 bool IOSChromePhysicalWebDataSource::HasUnresolvedDiscoveries() {
   return [scanner_ unresolvedBeaconsCount] > 0;
 }