Switch ChromeTestSuite to the same convention as ContentTestSuite:

chrome/browser/extensions/extension_prefs_unittest.cc

Index: chrome/browser/extensions/extension_prefs_unittest.cc
diff --git a/chrome/browser/extensions/extension_prefs_unittest.cc b/chrome/browser/extensions/extension_prefs_unittest.cc
index fd4da68f1fd43d8fca6cd1d37738c98521b1e980..f9a552a4a14e28150e4acc8f6ff4976703276552 100644
--- a/chrome/browser/extensions/extension_prefs_unittest.cc
+++ b/chrome/browser/extensions/extension_prefs_unittest.cc
@@ -15,7 +15,6 @@
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/extension_permission_set.h"
-#include "chrome/test/base/testing_browser_process_test.h"
 #include "content/browser/browser_thread.h"
 #include "content/common/notification_details.h"
 #include "content/common/notification_observer_mock.h"
@@ -46,7 +45,7 @@ static void AddPattern(URLPatternSet* extent, const std::string& pattern) {
 }
 
 // Base class for tests.
-class ExtensionPrefsTest : public TestingBrowserProcessTest {
+class ExtensionPrefsTest : public testing::Test {
  public:
   ExtensionPrefsTest()
       : ui_thread_(BrowserThread::UI, &message_loop_),