Show form validation message as a fallback tooltip.

third_party/WebKit/Source/core/html/HTMLInputElementTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/html/HTMLInputElement.h"
 
 #include "core/dom/Document.h"
 #include "core/html/HTMLBodyElement.h"
 #include "core/html/HTMLHtmlElement.h"
@@ skipping 30 matching lines @@
     EXPECT_NE(nullptr, document.frameHost());
 
     // Put the input element inside a document with frame.
     document.body()->appendChild(documentWithoutFrame->body()->firstChild());
 
     // Remove the input element and all refs to it so it gets deleted before the document.
     // The assert in |EventHandlerRegistry::updateEventHandlerTargets()| should not be triggered.
     document.body()->removeChild(document.body()->firstChild());
 }
 
+TEST(HTMLInputElementTest, DefaultToolTip)
+{
+    RefPtrWillBeRawPtr<Document> document = Document::create();
+    RefPtrWillBeRawPtr<HTMLHtmlElement> html = HTMLHtmlElement::create(*document);
+    html->appendChild(HTMLBodyElement::create(*document));
+    RefPtrWillBeRawPtr<HTMLInputElement> input = HTMLInputElement::create(*document, nullptr, false);
+    input->setBooleanAttribute(HTMLNames::requiredAttr, true);
+    toHTMLBodyElement(html->firstChild())->appendChild(input.get());
+    document->appendChild(html.release());
+    EXPECT_EQ("<<ValidationValueMissing>>", input->defaultToolTip());
+}
+
 } // namespace blink