Introduce class RelocatablePosition

third_party/WebKit/Source/core/editing/RelocatablePositionTest.cpp

+// Copyright 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/editing/RelocatablePosition.h"
+
+#include "core/editing/EditingTestBase.h"
+#include "core/editing/VisiblePosition.h"
+
+namespace blink {
+
+class RelocatablePositionTest : public EditingTestBase {
+};
+
+TEST_F(RelocatablePositionTest, position)
+{
+    setBodyContent("<b>foo</b><textarea>bar</textarea>");
+    Node* boldface = document().querySelector("b", ASSERT_NO_EXCEPTION);
+    Node* textarea = document().querySelector("textarea", ASSERT_NO_EXCEPTION);
+
+    RelocatablePosition relocatablePosition(Position(textarea, PositionAnchorType::BeforeAnchor));
+    textarea->remove();
+
+    // RelocatablePosition should track the given Position even if its original
+    // anchor node is moved away from the document.
+    Position expectedPosition(boldface, PositionAnchorType::AfterAnchor);
+    Position trackedPosition = relocatablePosition.position();
+    EXPECT_TRUE(trackedPosition.anchorNode()->inShadowIncludingDocument());
+    EXPECT_EQ(createVisiblePosition(expectedPosition).deepEquivalent(), createVisiblePosition(trackedPosition).deepEquivalent());
+}
+
+} // namespace blink