createFragmentFromMarkupWithContext() should use EphemeralRange.

third_party/WebKit/Source/core/editing/EphemeralRangeTest.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/EphemeralRange.h"
 
 #include "core/dom/Range.h"
 #include "core/editing/EditingTestBase.h"
 #include <sstream>
 
@@ skipping 130 matching lines @@
   // Tree iterators have only |operator !=| ATM.
   EXPECT_FALSE(iterable.begin() != iterable.end());
 
   const EphemeralRange singlePositionRange(getBodyRange()->startPosition());
   EXPECT_FALSE(singlePositionRange.isNull());
   EXPECT_EQ(std::string(), traverseRange(singlePositionRange));
   EXPECT_EQ(singlePositionRange.startPosition().nodeAsRangeFirstNode(),
             singlePositionRange.endPosition().nodeAsRangePastLastNode());
 }
 
+TEST_F(EphemeralRangeTest, commonAncesstorDOM) {
+  const char* bodyContent =
+      "<p id='host'>00<b id='one'>11</b><b id='two'>22</b><b "

[yosin_UTC9, 2017/03/06 07:35:30]

Could you use multiple lines string literal to better describing HTML structure?
"<p id="host">00"
  "<b id=one>11</b>"
  "<b id=two">22</b>"
  "<b id=three>33</b>"
"</p>"

If we don't care about whitespaces, can use raw string literal, e.g.
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/layout/ng...

R"HTML(
<p id="host">00
  <b id="one">11</b>
  <b id="two">22</b>
  <b id="three">33</b>
</p>)HTML"

[tanvir, 2017/03/06 14:42:01]

When i tried to do using staring literal, i was unable to upload the cl due to
format errors as below-:

Multi-line string ("...") found.  This lint script doesn't do well with such
strings, and may give bogus warnings.  They're ugly and unnecessary, and you
should use concatenation instead".  [readability/multiline_string]

This check-webkit-style error is only for cpp files, so i have used the first
method for now suggested by you.
Thanks

[yosin_UTC9, 2017/03/07 01:55:02]

Thanks for trying. It seems "raw string literal" hasn't been allowed in Blink
yet. It is allowed in Chromium.

+      "id='three'>33</b></p>";
+  setBodyContent(bodyContent);
+
+  const Position startPosition(document().getElementById("one"), 0);
+  const Position endPosition(document().getElementById("two"), 0);
+  const EphemeralRange range(startPosition, endPosition);
+  EXPECT_EQ(document().getElementById("host"), range.commonAncestorContainer());
+}
+
+TEST_F(EphemeralRangeTest, commonAncesstorFlatTree) {
+  const char* bodyContent =
+      "<b id=zero>0</b><p id=host><b id=one>1</b><b id=two>22</b></p><b "
+      "id=three>333</b>";
+  const char* shadowContent =
+      "<p id=four>4444</p><content select=#two></content><content "
+      "select=#one></content><p id=five>55555</p>";
+  setBodyContent(bodyContent);
+

[Xiaocheng, 2017/03/06 07:33:20]

nit: remove this extra blank line.

[tanvir, 2017/03/06 14:42:01]

Done.

+  ShadowRoot* shadowRoot = setShadowContent(shadowContent, "host");
+
+  const PositionInFlatTree startPosition(document().getElementById("one"), 0);
+  const PositionInFlatTree endPosition(shadowRoot->getElementById("five"), 0);
+  const EphemeralRangeInFlatTree range(startPosition, endPosition);
+  EXPECT_EQ(document().getElementById("host"), range.commonAncestorContainer());
+}
+
 }  // namespace blink