Start/stop WebKitThread from BrowserMainLoop like other BrowserThreads.

content/browser/in_process_webkit/webkit_thread_unittest.cc

 // Copyright (c) 2011 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 "content/browser/in_process_webkit/webkit_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using content::BrowserThread;
+namespace content {
 
 TEST(WebKitThreadTest, DISABLED_ExposedInBrowserThread) {
   int* null = NULL;  // Help the template system out.
   EXPECT_FALSE(BrowserThread::DeleteSoon(BrowserThread::WEBKIT,
                                          FROM_HERE, null));
   {
     WebKitThread thread;
     EXPECT_FALSE(BrowserThread::DeleteSoon(BrowserThread::WEBKIT,
                                            FROM_HERE, null));
     thread.Initialize();
     EXPECT_TRUE(BrowserThread::DeleteSoon(BrowserThread::WEBKIT,
                                           FROM_HERE, null));
   }
   EXPECT_FALSE(BrowserThread::DeleteSoon(BrowserThread::WEBKIT,
                                          FROM_HERE, null));
 }
+
+}  // namespace content