Pass Physical Web metadata through a struct

chrome/browser/android/physical_web/physical_web_data_source_android.h

Index: chrome/browser/android/physical_web/physical_web_data_source_android.h
diff --git a/chrome/browser/android/physical_web/physical_web_data_source_android.h b/chrome/browser/android/physical_web/physical_web_data_source_android.h
index 7704082a58556e9b736b1a1f61eb7cfa46f560cb..9e68b58fa9e65b37ea6210602963f75e9510e89e 100644
--- a/chrome/browser/android/physical_web/physical_web_data_source_android.h
+++ b/chrome/browser/android/physical_web/physical_web_data_source_android.h
@@ -27,7 +27,7 @@ class PhysicalWebCollection {
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jstring>& j_request_url,
       jdouble distance_estimate,
-      jint scan_timestamp,
+      jlong scan_timestamp,
       const base::android::JavaParamRef<jstring>& j_site_url,
       const base::android::JavaParamRef<jstring>& j_icon_url,
       const base::android::JavaParamRef<jstring>& j_title,
@@ -36,10 +36,17 @@ class PhysicalWebCollection {
 
   // Returns the metadata list and transfers ownership of the list to the
   // caller. Call only once.
-  std::unique_ptr<base::ListValue> GetMetadataList();
+  std::unique_ptr<physical_web::MetadataList> GetMetadataList();
+
+  // Returns the metadata list and transfers ownership of the list to the
+  // caller. Call only once.
+  // DEPRECATED
+  // TODO(cco3): Remove when we no longer rely on this.
+  std::unique_ptr<base::ListValue> GetMetadata();
 
  private:
-  std::unique_ptr<base::ListValue> metadata_list_;
+  std::unique_ptr<base::ListValue> dictionary_value_list_;
+  std::unique_ptr<physical_web::MetadataList> metadata_list_;
   bool accessed_once_;
 
   DISALLOW_COPY_AND_ASSIGN(PhysicalWebCollection);
@@ -59,6 +66,7 @@ class PhysicalWebDataSourceAndroid
   void StopDiscovery() override;
 
   std::unique_ptr<base::ListValue> GetMetadata() override;
+  std::unique_ptr<physical_web::MetadataList> GetMetadataList() override;
   bool HasUnresolvedDiscoveries() override;
 
   void OnFound(JNIEnv* env,