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

Source/core/html/HTMLTextFormControlElementTest.cpp

Index: Source/core/html/HTMLTextFormControlElementTest.cpp
diff --git a/Source/core/html/HTMLTextFormControlElementTest.cpp b/Source/core/html/HTMLTextFormControlElementTest.cpp
index d070470aeeb476ec8265375030dc9e56abe9656a..43f1117d600c0b2586e7cd5e56b464920ae58007 100644
--- a/Source/core/html/HTMLTextFormControlElementTest.cpp
+++ b/Source/core/html/HTMLTextFormControlElementTest.cpp
@@ -24,13 +24,11 @@
 #include "wtf/OwnPtr.h"
 #include <gtest/gtest.h>
 
-using namespace blink;
-
-namespace {
+namespace blink {
 
 class HTMLTextFormControlElementTest : public ::testing::Test {
 protected:
-    virtual void SetUp() override;
+    void SetUp() override;
 
     DummyPageHolder& page() const { return *m_dummyPageHolder; }
     HTMLDocument& document() const { return *m_document; }
@@ -225,4 +223,4 @@ TEST_F(HTMLTextFormControlElementTest, SpellCheckDoesNotCauseUpdateLayout)
     EXPECT_EQ(startCount, layoutCount());
 }
 
-}
+} // namespace blink