Allow multiple logging::LogMessage{Handler,Listener}s

chrome/test/base/web_ui_browser_test.h

 // 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.
 
 #ifndef CHROME_TEST_BASE_WEB_UI_BROWSER_TEST_H_
 #define CHROME_TEST_BASE_WEB_UI_BROWSER_TEST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 135 matching lines @@
   // Saves the states of |test_fixture| and |test_name| for calling
   // PreloadJavascriptLibraries().
   std::string preload_test_fixture_;
   std::string preload_test_name_;
 
   // When this is non-NULL, this is The WebUI instance used for testing.
   // Otherwise the selected tab's web_ui is used.
   content::WebUI* override_selected_web_ui_;
 
   std::unique_ptr<TestChromeWebUIControllerFactory> test_factory_;
+
+  logging::ScopedLogMessageListener listener;
 };
 
 #endif  // CHROME_TEST_BASE_WEB_UI_BROWSER_TEST_H_