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

chrome/test/base/web_ui_browser_test.h

Index: chrome/test/base/web_ui_browser_test.h
diff --git a/chrome/test/base/web_ui_browser_test.h b/chrome/test/base/web_ui_browser_test.h
index b642fd083b87024d70887e2b86fd3729cb41a42a..2daf50f8f679de378dc27090ae6e0f0e59eac883 100644
--- a/chrome/test/base/web_ui_browser_test.h
+++ b/chrome/test/base/web_ui_browser_test.h
@@ -25,6 +25,15 @@ class WebUIMessageHandler;
 class TestChromeWebUIControllerFactory;
 class WebUITestHandler;
 
+class WebUILogMessageListener : logging::LogMessageListener {
+ public:
+  void OnMessage(int severity,
+                 const char* file,
+                 int line,
+                 size_t message_start,
+                 const std::string& str) override;
+};
+
 // The runner of WebUI javascript based tests.
 // See chrome/test/data/webui/test_api.js for the javascript side test API's.
 //
@@ -153,6 +162,8 @@ class WebUIBrowserTest : public JavaScriptBrowserTest {
   content::WebUI* override_selected_web_ui_;
 
   std::unique_ptr<TestChromeWebUIControllerFactory> test_factory_;
+
+  WebUILogMessageListener log_listener_;
 };
 
 #endif  // CHROME_TEST_BASE_WEB_UI_BROWSER_TEST_H_