Add a Physical Web data source

ios/chrome/common/physical_web/physical_web_data_source_ios.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/common/physical_web/physical_web_data_source_ios.h"
+
+void PhysicalWebDataSourceIOS::StartDiscovery(bool network_request_enabled) {
+  // If there are unresolved beacons it means the scanner is started but does
+  // not have network requests enabled. In this case we should avoid recreating
+  // the scanner as it would clear the cache of nearby beacons.
+  if (network_request_enabled && HasUnresolvedDiscoveries()) {
+    [scanner_ setNetworkRequestEnabled:YES];
+    return;
+  }
+
+  [scanner_ stop];
+  scanner_.reset([[PhysicalWebScanner alloc] initWithDelegate:nil]);
+  [scanner_ setNetworkRequestEnabled:(BOOL)network_request_enabled];

[Olivier, 2016/06/30 08:14:11]

no C cast.
Use static_cast<BOOL> instead

[mattreynolds, 2016/06/30 17:51:58]

Done.

+  [scanner_ start];
+}
+
+void PhysicalWebDataSourceIOS::StopDiscovery() {
+  [scanner_ stop];
+  scanner_.reset();
+}
+
+std::unique_ptr<base::ListValue> PhysicalWebDataSourceIOS::GetMetadata() {
+  std::unique_ptr<base::ListValue> metadata = [scanner_ metadata];
+  if (metadata.get() == NULL) {
+    metadata.reset(new base::ListValue());
+  }
+  return metadata;
+}
+
+bool PhysicalWebDataSourceIOS::HasUnresolvedDiscoveries() {
+  return [scanner_ unresolvedBeaconsCount] > 0;
+}
+
+PhysicalWebDataSourceIOS::PhysicalWebDataSourceIOS() {}
+
+PhysicalWebDataSourceIOS::~PhysicalWebDataSourceIOS() {
+  StopDiscovery();
+}