Start/stop WebKitThread from BrowserMainLoop like other BrowserThreads.

content/browser/in_process_webkit/webkit_thread_unittest.cc

Index: content/browser/in_process_webkit/webkit_thread_unittest.cc
diff --git a/content/browser/in_process_webkit/webkit_thread_unittest.cc b/content/browser/in_process_webkit/webkit_thread_unittest.cc
index 6662ed43bbce1151620f45afc9dba3268ca57c2b..07a729f1331c1eb7ec11f4b4fc073c71ac559d2c 100644
--- a/content/browser/in_process_webkit/webkit_thread_unittest.cc
+++ b/content/browser/in_process_webkit/webkit_thread_unittest.cc
@@ -5,7 +5,7 @@
 #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.
@@ -22,3 +22,5 @@ TEST(WebKitThreadTest, DISABLED_ExposedInBrowserThread) {
   EXPECT_FALSE(BrowserThread::DeleteSoon(BrowserThread::WEBKIT,
                                          FROM_HERE, null));
 }
+
+}  // namespace content