Move Node::lengthOfContents into Range, its only user.

third_party/WebKit/Source/core/dom/AttrTest.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 "core/dom/Attr.h"
 
 #include "core/dom/Document.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 44 matching lines @@
 }
 
 TEST_F(AttrTest, SetTextContent) {
   Attr* attr = createAttribute();
   attr->setTextContent(value());
   EXPECT_EQ(value(), attr->value());
   EXPECT_EQ(value(), attr->toNode()->nodeValue());
   EXPECT_EQ(value(), attr->textContent());
 }
 
-TEST_F(AttrTest, LengthOfContents) {
-  Attr* attr = createAttribute();
-  EXPECT_EQ(0u, attr->lengthOfContents());
-  attr->setValue(value());
-  EXPECT_EQ(0u, attr->lengthOfContents());
-}
-
 }  // namespace blink