Make Text::updateLayoutTextObject() to handle first-letter pseudo element correctly

third_party/WebKit/Source/core/dom/TextTest.cpp

 // Copyright (c) 2016 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 "core/dom/Text.h"
 
 #include "core/dom/Range.h"
 #include "core/editing/EditingTestBase.h"
 #include "core/html/HTMLPreElement.h"
 #include "core/layout/LayoutText.h"
 
 namespace blink {
 
 // TODO(xiaochengh): Use a new testing base class.
 class TextTest : public EditingTestBase {
 };
 
+TEST_F(TextTest, SetDataToChangeFirstLetterTextNode)
+{
+    setBodyContent("<style>pre::first-letter {color:red;}</style><pre id=sample>a<span>b</span></pre>");
+
+    Node* sample = document().getElementById("sample");
+    Text* text = toText(sample->firstChild());
+    text->setData(" ");
+    updateAllLifecyclePhases();
+
+    EXPECT_FALSE(text->layoutObject()->isTextFragment());
+}
+
 TEST_F(TextTest, RemoveFirstLetterPseudoElementWhenNoLetter)
 {
     setBodyContent("<style>*::first-letter{font:icon;}</style><pre>AB\n</pre>");
 
     Element* pre = document().querySelector("pre", ASSERT_NO_EXCEPTION);
     Text* text = toText(pre->firstChild());
 
     Range* range = Range::create(document(), text, 0, text, 2);
     range->deleteContents(ASSERT_NO_EXCEPTION);
     updateAllLifecyclePhases();
 
     EXPECT_FALSE(text->layoutObject()->isTextFragment());
 }
 
 } // namespace blink