Add other variations (with ids) for NTPSnippets to chrome://flags

components/flags_ui/flags_state.h

Index: components/flags_ui/flags_state.h
diff --git a/components/flags_ui/flags_state.h b/components/flags_ui/flags_state.h
index 2be899cc05e89824fab6a31d6cce6ce228010e48..7d7e933e9b087a6c70fa26c36ff15227c54f5e6a 100644
--- a/components/flags_ui/flags_state.h
+++ b/components/flags_ui/flags_state.h
@@ -10,6 +10,7 @@
 #include <map>
 #include <set>
 #include <string>
+#include <vector>
 
 #include "base/callback_forward.h"
 #include "base/command_line.h"
@@ -84,9 +85,12 @@ class FlagsState {
   // Registers variations parameter values selected for features in about:flags.
   // The selected flags are retrieved from |flags_storage|, the registered
   // variation parameters are connected to their corresponding features in
-  // |feature_list|.
-  void RegisterAllFeatureVariationParameters(FlagsStorage* flags_storage,
-                                             base::FeatureList* feature_list);
+  // |feature_list|. Returns the (possibly empty) comma separated list of
+  // additional variation ids to register in the MetricsService that come from
+  // variations selected using chrome://flags.
+  std::vector<std::string> RegisterAllFeatureVariationParameters(
+      FlagsStorage* flags_storage,
+      base::FeatureList* feature_list);
 
   // Gets the list of feature entries. Entries that are available for the
   // current platform are appended to |supported_entries|; all other entries are