Pass Physical Web metadata through a struct

components/physical_web/data_source/physical_web_data_source.h

Index: components/physical_web/data_source/physical_web_data_source.h
diff --git a/components/physical_web/data_source/physical_web_data_source.h b/components/physical_web/data_source/physical_web_data_source.h
index c6310396ce1a25c4ac2a767975182c3def46f550..43e007c4cff301500dd98782f09eaa4876d7a424 100644
--- a/components/physical_web/data_source/physical_web_data_source.h
+++ b/components/physical_web/data_source/physical_web_data_source.h
@@ -6,6 +6,10 @@
 #define COMPONENTS_PHYSICAL_WEB_DATA_SOURCE_PHYSICAL_WEB_DATA_SOURCE_H_
 
 #include <memory>
+#include <string>
+#include <vector>
+#include "base/time/time.h"
+#include "url/gurl.h"
 
 namespace base {
 class ListValue;
@@ -16,6 +20,7 @@ namespace physical_web {
 class PhysicalWebListener;
 
 // Dictionary keys for reading Physical Web URL metadata.
+// TODO(cco3): Remove these when we are no longer dependent.
 extern const char kDescriptionKey[];
 extern const char kDistanceEstimateKey[];
 extern const char kGroupIdKey[];
@@ -25,6 +30,35 @@ extern const char kScanTimestampKey[];
 extern const char kScannedUrlKey[];
 extern const char kTitleKey[];
 
+// Metadata struct for associating data with Physical Web URLs.
+struct Metadata {

[mattreynolds, 2016/12/09 00:10:03]

We should comment on which fields are optional. IIRC, at the PWS level the
scanned_url and resolved_url are required, and at least one of title or
description is required. On iOS we only set scanned_url, resolved_url, icon_url,
title, and description.

distance_estimate should probably be optional, maybe we should document it as
returning -1.0 when no distance estimate is available? (what do we do now?)

icon_url is definitely optional, group_id and scan_timestamp should be required
(but currently aren't).

+  Metadata();
+  Metadata(const Metadata& other);
+  ~Metadata();
+  // The URL broadcasted by the beacon and scanned by the client device.
+  GURL scanned_url;
+  // The URL that the scanned_url redirects to.
+  // This is the URL that users should be directed to.
+  GURL resolved_url;
+  // The favicon URL.
+  GURL icon_url;
+  // The title of the web page.
+  std::string title;
+  // The description of the web page.
+  std::string description;
+  // An identifier that associates multiple resolved URLs.  If two URLs have
+  // the same group id, only one should be shown (typically, the one with the
+  // smallest distance estimate).
+  std::string group_id;
+  // The estimated distance between the user and the Physical Web device (e.g.,
+  // beacon) in meters.
+  double distance_estimate;
+  // The timestamp corresponding to when this URL was last scanned.
+  base::Time scan_timestamp;
+};
+
+using MetadataList = std::vector<Metadata>;
+
 // Helper class for accessing Physical Web metadata and controlling the scanner.
 class PhysicalWebDataSource {
  public:
@@ -41,6 +75,14 @@ class PhysicalWebDataSource {
   // requests are disabled or if discovery is not active, the list will be
   // empty. The method can be called at any time to receive the current metadata
   // list.
+  virtual std::unique_ptr<MetadataList> GetMetadataList() = 0;
+
+  // Returns a list of resolved URLs and associated page metadata. If network
+  // requests are disabled or if discovery is not active, the list will be
+  // empty. The method can be called at any time to receive the current metadata
+  // list.
+  // DEPRECATED
+  // TODO(cco3): Remove this when we are no longer dependent on it.
   virtual std::unique_ptr<base::ListValue> GetMetadata() = 0;
 
   // Returns boolean |true| if network requests are disabled and there are one