Add a Physical Web data source

ios/chrome/common/physical_web/ios_chrome_physical_web_data_source.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_COMMON_PHYSICAL_WEB_IOS_CHROME_PHYSICAL_WEB_DATA_SOURCE_H_
+#define IOS_CHROME_COMMON_PHYSICAL_WEB_IOS_CHROME_PHYSICAL_WEB_DATA_SOURCE_H_
+
+#include "base/macros.h"
+#include "base/values.h"
+#import "base/mac/scoped_nsobject.h"
+#include "components/physical_web/data_source/physical_web_data_source.h"
+#import "ios/chrome/common/physical_web/physical_web_scanner.h"
+
+// iOS implementation of PhysicalWebDataSource

[blundell, 2016/07/28 11:12:25]

Will this class only be used by Chrome on iOS (i.e., not by the Today
extension)? If so, it seems like it could be in //ios/chrome/browser, be a
BrowserStateKeyedService, and get around the singleton problem that way. There
would then be one PhysicalWebScanner instance per ChromeBrowserState but from
looking at that class that doesn't seem problematic to me (correct me if I'm
wrong though).

[mattreynolds, 2016/07/29 01:36:31]

The Today extension will most likely not use this class.

+class IOSChromePhysicalWebDataSource : public PhysicalWebDataSource {
+ public:
+  IOSChromePhysicalWebDataSource();
+  ~IOSChromePhysicalWebDataSource() override;
+
+  // Starts scanning for Physical Web URLs. If |network_request_enabled| is
+  // true, discovered URLs will be sent to a resolution service.
+  void StartDiscovery(bool network_request_enabled) override;
+
+  // Stops scanning for Physical Web URLs and clears cached URL content.
+  void StopDiscovery() override;
+
+  // Returns a list of resolved URLs and associated page metadata. If network
+  // requests are disabled, the list will be empty.
+  std::unique_ptr<base::ListValue> GetMetadata() override;
+
+  // Returns boolean |true| if network requests are disabled and there are one
+  // or more discovered URLs that have not been sent to the resolution service.
+  bool HasUnresolvedDiscoveries() override;
+
+ private:
+  // Scanner for nearby Physical Web URL devices.
+  base::scoped_nsobject<PhysicalWebScanner> scanner_;
+
+  DISALLOW_COPY_AND_ASSIGN(IOSChromePhysicalWebDataSource);
+};
+
+#endif  // IOS_CHROME_COMMON_PHYSICAL_WEB_IOS_CHROME_PHYSICAL_WEB_DATA_SOURCE_H_