Index: src/wp-includes/general-template.php
===================================================================
--- src/wp-includes/general-template.php	(revision 41656)
+++ src/wp-includes/general-template.php	(working copy)
@@ -403,6 +403,10 @@
 		'id_submit' => 'wp-submit',
 		'remember' => true,
 		'value_username' => '',
+		// Set 'input_username_required' to true will make username input field required
+		'input_username_required' => false,
+		// Set 'input_password_required' to true will make password input field required
+		'input_password_required' => false,
 		// Set 'value_remember' to true to default the "Remember me" checkbox to checked.
 		'value_remember' => false,
 	);
@@ -455,16 +459,21 @@
 	 */
 	$login_form_bottom = apply_filters( 'login_form_bottom', '', $args );
 
+	// If username input field is required.
+	$input_username_required = $args['input_username_required'] ? 'required' : '';
+	// If password input field is required.
+	$input_password_required = $args['input_password_required'] ? 'required' : '';
+
 	$form = '
 		<form name="' . $args['form_id'] . '" id="' . $args['form_id'] . '" action="' . esc_url( site_url( 'wp-login.php', 'login_post' ) ) . '" method="post">
 			' . $login_form_top . '
 			<p class="login-username">
 				<label for="' . esc_attr( $args['id_username'] ) . '">' . esc_html( $args['label_username'] ) . '</label>
-				<input type="text" name="log" id="' . esc_attr( $args['id_username'] ) . '" class="input" value="' . esc_attr( $args['value_username'] ) . '" size="20" />
+				<input type="text" name="log" id="' . esc_attr( $args['id_username'] ) . '" class="input" value="' . esc_attr( $args['value_username'] ) . '" size="20" ' . esc_attr( $input_username_required ) . '/>
 			</p>
 			<p class="login-password">
 				<label for="' . esc_attr( $args['id_password'] ) . '">' . esc_html( $args['label_password'] ) . '</label>
-				<input type="password" name="pwd" id="' . esc_attr( $args['id_password'] ) . '" class="input" value="" size="20" />
+				<input type="password" name="pwd" id="' . esc_attr( $args['id_password'] ) . '" class="input" value="" size="20" ' . esc_attr( $input_password_required ) . '/>
 			</p>
 			' . $login_form_middle . '
 			' . ( $args['remember'] ? '<p class="login-remember"><label><input name="rememberme" type="checkbox" id="' . esc_attr( $args['id_remember'] ) . '" value="forever"' . ( $args['value_remember'] ? ' checked="checked"' : '' ) . ' /> ' . esc_html( $args['label_remember'] ) . '</label></p>' : '' ) . '