Add instrumentation for password autofill and Credential Manager API user flows.

components/password_manager/core/browser/password_form_manager.h

Index: components/password_manager/core/browser/password_form_manager.h
diff --git a/components/password_manager/core/browser/password_form_manager.h b/components/password_manager/core/browser/password_form_manager.h
index faaa9cee916aad8cf2c0b47085abde272c1025ce..1dffb756cfbda3a522fddfd6a19b173633a17b9f 100644
--- a/components/password_manager/core/browser/password_form_manager.h
+++ b/components/password_manager/core/browser/password_form_manager.h
@@ -282,7 +282,7 @@ class PasswordFormManager : public PasswordStoreConsumer {
   enum ManagerAction {
     kManagerActionNone = 0,
     kManagerActionAutofilled,
-    kManagerActionBlacklisted,
+    kManagerActionBlacklisted_Obsolete,
     kManagerActionMax
   };
 
@@ -462,6 +462,9 @@ class PasswordFormManager : public PasswordStoreConsumer {
   // Send appropriate votes based on what is currently being saved.
   void SendVotesOnSave();
 
+  // Sets |user_action_| and records some metrics.
+  void SetUserAction(UserAction user_action);
+
   // Edits some fields in |pending_credentials_| before it can be used to
   // update the password store. It also goes through |not_best_matches|,
   // updates the password of those which share the old password and username