Fix unit test style in core/{dom,editing,html}/.

Source/core/dom/TreeScopeTest.cpp

 // Copyright 2014 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 "config.h"
 #include "core/dom/TreeScope.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include <gtest/gtest.h>
 
-using namespace blink;
-
-namespace {
+namespace blink {
 
 TEST(TreeScopeTest, CommonAncestorOfSameTrees)
 {
     RefPtrWillBeRawPtr<Document> document = Document::create();
     EXPECT_EQ(document.get(), document->commonAncestorTreeScope(*document));
 
     RefPtrWillBeRawPtr<Element> html = document->createElement("html", nullAtom, ASSERT_NO_EXCEPTION);
     document->appendChild(html, ASSERT_NO_EXCEPTION);
     RefPtrWillBeRawPtr<ShadowRoot> shadowRoot = html->createShadowRoot(ASSERT_NO_EXCEPTION);
     EXPECT_EQ(shadowRoot.get(), shadowRoot->commonAncestorTreeScope(*shadowRoot));
@@ skipping 63 matching lines @@
 }
 
 TEST(TreeScopeTest, CommonAncestorOfTreesInDifferentDocuments)
 {
     RefPtrWillBeRawPtr<Document> document1 = Document::create();
     RefPtrWillBeRawPtr<Document> document2 = Document::create();
     EXPECT_EQ(0, document1->commonAncestorTreeScope(*document2));
     EXPECT_EQ(0, document2->commonAncestorTreeScope(*document1));
 }
 
-} // namespace
+} // namespace blink