[Password Manager] Add UMA stats to track interaction with synced accounts.

components/password_manager/core/browser/login_database.h

Index: components/password_manager/core/browser/login_database.h
diff --git a/components/password_manager/core/browser/login_database.h b/components/password_manager/core/browser/login_database.h
index ac6bd0be6349d353d8421c7854e40c7a197d4b7f..de549ec350c963d5491272f8a309a317533480d8 100644
--- a/components/password_manager/core/browser/login_database.h
+++ b/components/password_manager/core/browser/login_database.h
@@ -16,6 +16,9 @@
 #include "sql/connection.h"
 #include "sql/meta_table.h"
 
+class ProfileSyncService;
+class SigninManagerBase;
+
 namespace password_manager {
 
 // Interface to the database storage of login information, intended as a helper
@@ -31,7 +34,8 @@ class LoginDatabase {
   bool Init(const base::FilePath& db_path);
 
   // Reports usage metrics to UMA.
-  void ReportMetrics();
+  void ReportMetrics(const std::string& sync_username,
+                     enum SyncState sync_state);
 
   // Adds |form| to the list of remembered password forms. Returns the list of
   // changes applied ({}, {ADD}, {REMOVE, ADD}). If it returns {REMOVE, ADD}