Make Range::createAdjustedToTreeScope() to handle the shadow root at end of document tree correctly.

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

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Gunnstein Lye (gunnstein@netcom.no)
  * (C) 2000 Frederik Holljen (frederik.holljen@hig.no)
  * (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2011 Motorola Mobility. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 82 matching lines @@
 
 Range* Range::create(Document& ownerDocument,
                      const Position& start,
                      const Position& end) {
   return new Range(ownerDocument, start.computeContainerNode(),
                    start.computeOffsetInContainerNode(),
                    end.computeContainerNode(),
                    end.computeOffsetInContainerNode());
 }
 
+// TODO(yosin): We should move |Range::createAdjustedToTreeScope()| to
+// "Document.cpp" since it is use only one place in "Document.cpp".
 Range* Range::createAdjustedToTreeScope(const TreeScope& treeScope,
                                         const Position& position) {
-  Range* range = create(treeScope.document(), position, position);
-
-  // Make sure the range is in this scope.
-  Node* firstNode = range->firstNode();
-  DCHECK(firstNode);
-  Node* shadowHostInThisScopeOrFirstNode =
-      treeScope.ancestorInThisScope(firstNode);
-  DCHECK(shadowHostInThisScopeOrFirstNode);
-  if (shadowHostInThisScopeOrFirstNode == firstNode)
-    return range;
-
-  // If not, create a range for the shadow host in this scope.
-  ContainerNode* container = shadowHostInThisScopeOrFirstNode->parentNode();
-  DCHECK(container);
-  unsigned offset = shadowHostInThisScopeOrFirstNode->nodeIndex();
-  return Range::create(treeScope.document(), container, offset, container,
-                       offset);
+  DCHECK(position.isNotNull());
+  // Note: Since |Position::computeContanerNode()| returns |nullptr| if
+  // |position| is |BeforeAnchor| or |AfterAnchor|.
+  Node* const anchorNode = position.anchorNode();
+  if (anchorNode->treeScope() == treeScope)
+    return create(treeScope.document(), position, position);
+  Node* const shadowHost = treeScope.ancestorInThisScope(anchorNode);
+  return Range::create(treeScope.document(), Position::beforeNode(shadowHost),
+                       Position::beforeNode(shadowHost));
 }
 
 void Range::dispose() {
   // A prompt detach from the owning Document helps avoid GC overhead.
   m_ownerDocument->detachRange(this);
 }
 
 bool Range::isConnected() const {
   DCHECK_EQ(m_start.isConnected(), m_end.isConnected());
   return m_start.isConnected();
@@ skipping 1639 matching lines @@
                      .data()
               << "start offset: " << range->startOffset()
               << ", end offset: " << range->endOffset();
   } else {
     LOG(INFO) << "Cannot show tree if range is null, or if boundary points are "
                  "invalid.";
   }
 }
 
 #endif