Make rendersInDifferentPosition() to work with AfterAnchor and AfterChildren positions properly

Source/core/dom/PositionTest.cpp

 // Copyright 2015 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/dom/Position.h"
 
 #include "core/editing/EditingTestBase.h"
 
 namespace blink {
@@ skipping 84 matching lines @@
     EXPECT_EQ(t2, Position::inParentAfterNode(*n2).nodeAsRangeLastNode());
     EXPECT_EQ(t3, Position::afterNode(host).nodeAsRangeLastNode());
 
     EXPECT_EQ(t2, PositionInComposedTree::inParentBeforeNode(*n1).nodeAsRangeLastNode());
     EXPECT_EQ(a, PositionInComposedTree::inParentBeforeNode(*n2).nodeAsRangeLastNode());
     EXPECT_EQ(t1, PositionInComposedTree::inParentAfterNode(*n1).nodeAsRangeLastNode());
     EXPECT_EQ(t2, PositionInComposedTree::inParentAfterNode(*n2).nodeAsRangeLastNode());
     EXPECT_EQ(t1, PositionInComposedTree::afterNode(host).nodeAsRangeLastNode());
 }
 
+TEST_F(PositionTest, rendersInDifferentPositionAfterAnchor)
+{
+    const char* bodyContent = "<p id='sample'>00</p>";
+    setBodyContent(bodyContent);
+    updateLayoutAndStyleForPainting();
+    RefPtrWillBeRawPtr<Element> sample = document().getElementById("sample");
+
+    EXPECT_FALSE(Position::afterNode(sample.get()).rendersInDifferentPosition(Position(sample.get(), 1)));
+    EXPECT_FALSE(Position::lastPositionInNode(sample.get()).rendersInDifferentPosition(Position(sample.get(), 1)));
+}
+
 TEST_F(PositionTest, ToPositionInComposedTreeWithActiveInsertionPoint)
 {
     const char* bodyContent = "<p id='host'>00<b id='one'>11</b>22</p>";
     const char* shadowContent = "<a id='a'><content select=#one id='content'></content><content></content></a>";
     setBodyContent(bodyContent);
     RefPtrWillBeRawPtr<ShadowRoot> shadowRoot = setShadowContent(shadowContent);
     RefPtrWillBeRawPtr<Element> anchor = shadowRoot->getElementById("a");
 
     EXPECT_EQ(PositionInComposedTree(anchor.get(), 0), toPositionInComposedTree(Position(anchor.get(), 0)));
     EXPECT_EQ(PositionInComposedTree(anchor.get(), 1), toPositionInComposedTree(Position(anchor.get(), 1)));
@@ skipping 55 matching lines @@
 
     RefPtrWillBeRawPtr<Element> host = document().getElementById("host");
     RefPtrWillBeRawPtr<Element> one = document().getElementById("one");
     RefPtrWillBeRawPtr<Element> three = shadowRoot->getElementById("three");
 
     EXPECT_EQ(Position(one->firstChild(), 1), Position::afterNode(host.get()).upstream());
     EXPECT_EQ(PositionInComposedTree(three->firstChild(), 3), PositionInComposedTree::afterNode(host.get()).upstream());
 }
 
 } // namespace blink