Use NodeAsRangeFirstNode() as Range::FirstNode() again.

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

Index: third_party/WebKit/Source/core/dom/Range.cpp
diff --git a/third_party/WebKit/Source/core/dom/Range.cpp b/third_party/WebKit/Source/core/dom/Range.cpp
index deae19228de4b177d043485e624d0bb0a9d22e8b..e092d2aa29f24105f1e128f5a4b9615e522e3554 100644
--- a/third_party/WebKit/Source/core/dom/Range.cpp
+++ b/third_party/WebKit/Source/core/dom/Range.cpp
@@ -1433,21 +1433,11 @@ void Range::CheckExtractPrecondition(ExceptionState& exception_state) {
 }
 
 Node* Range::FirstNode() const {
-  if (start_.Container().IsCharacterDataNode())
-    return &start_.Container();
-  if (Node* child = NodeTraversal::ChildAt(start_.Container(), start_.Offset()))
-    return child;
-  if (!start_.Offset())
-    return &start_.Container();
-  return NodeTraversal::NextSkippingChildren(start_.Container());
+  return StartPosition().ToOffsetInAnchor().NodeAsRangeFirstNode();

[yosin_UTC9, 2017/04/13 05:45:45]

We don't need to use |ToOffsetInAnchor()| here.
|Position::NodeAsRangeFirstNode()| does so.
BTW, we would like to call |ToOffsetInAnchor()| in
|Position::NodeAsRangeFirstNode()|.

[yoichio, 2017/04/13 06:04:39]

Done.

 }
 
 Node* Range::PastLastNode() const {
-  if (end_.Container().IsCharacterDataNode())
-    return NodeTraversal::NextSkippingChildren(end_.Container());
-  if (Node* child = NodeTraversal::ChildAt(end_.Container(), end_.Offset()))
-    return child;
-  return NodeTraversal::NextSkippingChildren(end_.Container());
+  return EndPosition().ToOffsetInAnchor().NodeAsRangePastLastNode();

[yosin_UTC9, 2017/04/13 05:45:45]

We don't need to use |ToOffsetInAnchor()| here.
|Position::NodeAsRangePastLastNode()| does so.
BTW, we would like to call |ToOffsetInAnchor()| in
|Position::NodeAsRangePastLastNode()|.

[yoichio, 2017/04/13 06:04:39]

Done.

 }
 
 IntRect Range::BoundingBox() const {