Remove GetMetadata from PhysicalWebDataSource and PhysicalWebScanner

ios/chrome/common/physical_web/physical_web_scanner.h

Index: ios/chrome/common/physical_web/physical_web_scanner.h
diff --git a/ios/chrome/common/physical_web/physical_web_scanner.h b/ios/chrome/common/physical_web/physical_web_scanner.h
index 354fdfc9c9cfd361b2ef71bd80d5700bf7ffe6f1..5cb2d4531bd72edab5a46e5d4498b46ea4816d46 100644
--- a/ios/chrome/common/physical_web/physical_web_scanner.h
+++ b/ios/chrome/common/physical_web/physical_web_scanner.h
@@ -10,10 +10,6 @@
 #include <memory>
 #include <vector>
 
-namespace base {
-class ListValue;
-}
-
 namespace physical_web {
 struct Metadata;
 using MetadataList = std::vector<Metadata>;
@@ -59,12 +55,7 @@ using MetadataList = std::vector<Metadata>;
 - (NSArray*)devices;
 
 // Returns the metadata for all resolved physical web URLs. The returned value
-// will never be nil; if no metadata has been received then an empty list is
-// returned.
-- (std::unique_ptr<base::ListValue>)metadata;
-
-// Returns the metadata for all resolved physical web URLs. The returned value
-// will never be nil; if no metadata has been received then an empty list is
+// will never be null; if no metadata has been received then an empty list is
 // returned.
 - (std::unique_ptr<physical_web::MetadataList>)metadataList;