createFragmentFromMarkupWithContext() should use EphemeralRange.

third_party/WebKit/Source/core/editing/EphemeralRange.h

 // 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.
 
 #ifndef EphemeralRange_h
 #define EphemeralRange_h
 
 #include "core/editing/Position.h"
 
 namespace blink {
@@ skipping 87 matching lines @@
   EphemeralRangeTemplate<Strategy>& operator=(
       const EphemeralRangeTemplate<Strategy>& other);
 
   bool operator==(const EphemeralRangeTemplate<Strategy>& other) const;
   bool operator!=(const EphemeralRangeTemplate<Strategy>& other) const;
 
   Document& document() const;
   PositionTemplate<Strategy> startPosition() const;
   PositionTemplate<Strategy> endPosition() const;
 
+  Node* commonAncestorContainer() const;

[Xiaocheng, 2017/02/28 19:26:31]

Could you add unit tests for this new function?

At least two unit tests are needed, with one for DOM tree and another for flat
tree (*).

(*) https://www.w3.org/TR/shadow-dom/

[tanvir, 2017/03/02 14:59:14]

I have added the unit test cases for DOM and FlatTree.

[tanvir, 2017/03/02 14:59:14]

Done.

+  static Node* commonAncestorContainer(const Node* containerA, const Node* containerB);

[Xiaocheng, 2017/02/28 19:26:31]

There's no need to expose this function, as there's no external caller.

I think it's better to just hide it in EphemeralRange.cpp in an anonymous
namespace. You may follow the coding style in EditingUtilities.cpp

[tanvir, 2017/03/02 14:59:14]

Done.

+
   // Returns true if |m_startPositoin| == |m_endPosition| or |isNull()|.
   bool isCollapsed() const;
   bool isNull() const {
     DCHECK(isValid());
     return m_startPosition.isNull();
   }
   bool isNotNull() const { return !isNull(); }
 
   RangeTraversal nodes() const;
 
@@ skipping 21 matching lines @@
 using EphemeralRangeInFlatTree =
     EphemeralRangeTemplate<EditingInFlatTreeStrategy>;
 
 // Returns a newly created |Range| object from |range| or |nullptr| if
 // |range.isNull()| returns true.
 CORE_EXPORT Range* createRange(const EphemeralRange& /* range */);
 
 }  // namespace blink
 
 #endif