Sandbox should prevent 'execCommand("print", ...)'.

third_party/WebKit/LayoutTests/http/tests/security/sandbox-iframe-blocks-modals.php

Index: third_party/WebKit/LayoutTests/http/tests/security/sandbox-iframe-blocks-modals.php
diff --git a/third_party/WebKit/LayoutTests/http/tests/security/sandbox-iframe-blocks-modals.php b/third_party/WebKit/LayoutTests/http/tests/security/sandbox-iframe-blocks-modals.php
index b1a434cfd1bcb107923f73d47296dc9c967c8355..a28e8b9c712dc95d5a9bbb37dd11436ae8cb0cd3 100644
--- a/third_party/WebKit/LayoutTests/http/tests/security/sandbox-iframe-blocks-modals.php
+++ b/third_party/WebKit/LayoutTests/http/tests/security/sandbox-iframe-blocks-modals.php
@@ -20,6 +20,11 @@ header("Content-Security-Policy: sandbox allow-scripts");
         }, "print() returns synchronously in a sandboxed page without blocking on user input.");
 
         test(function () {
+            var result = document.execCommand('print', false, null);
+            assert_false(result);
+        }, "execCommand('print', ...) returns synchronously in a sandboxed page without blocking on user input.");
+
+        test(function () {
             var result = confirm("Question?");
             assert_equals(result, false);
         }, "confirm() returns 'false' synchronously in a sandboxed page without blocking on user input.");