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

components/password_manager/core/browser/test_password_store.h

Index: components/password_manager/core/browser/test_password_store.h
diff --git a/components/password_manager/core/browser/test_password_store.h b/components/password_manager/core/browser/test_password_store.h
index e8b243331e27ccba4a4faed61e8bd254e7c91ffa..52b52c43a204c965dc05d9a30dfef3f435fd865b 100644
--- a/components/password_manager/core/browser/test_password_store.h
+++ b/components/password_manager/core/browser/test_password_store.h
@@ -58,7 +58,7 @@ class TestPasswordStore : public PasswordStore {
   virtual void WrapModificationTask(ModificationTask task) OVERRIDE;
 
   // Unused portions of PasswordStore interface
-  virtual void ReportMetricsImpl() OVERRIDE {}
+  virtual void ReportMetricsImpl(const std::string& sync_username) OVERRIDE {}
   virtual PasswordStoreChangeList RemoveLoginsCreatedBetweenImpl(
       base::Time begin,
       base::Time end) OVERRIDE;