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

chrome/browser/media/webrtc_browsertest_base.h

Index: chrome/browser/media/webrtc_browsertest_base.h
diff --git a/chrome/browser/media/webrtc_browsertest_base.h b/chrome/browser/media/webrtc_browsertest_base.h
index d4d6dcd495d24c8b74fc0daa8cb6c4d5dd75f20c..7669c16af54e5a1a41eac77de19d9a8619df62c1 100644
--- a/chrome/browser/media/webrtc_browsertest_base.h
+++ b/chrome/browser/media/webrtc_browsertest_base.h
@@ -18,6 +18,12 @@ namespace content {
 class WebContents;
 }
 
+class JavascriptErrorDetectingListener : logging::LogMessageListener {
+ public:
+  void OnMessage(int severity, const char* file, int line,
+      size_t message_start, const std::string& str) override;
+};
+
 // Base class for WebRTC browser tests with useful primitives for interacting
 // getUserMedia. We use inheritance here because it makes the test code look
 // as clean as it can be.
@@ -187,6 +193,7 @@ class WebRtcTestBase : public InProcessBrowserTest {
       content::WebContents* tab_contents,
       const std::string& constraints) const;
 
+  JavascriptErrorDetectingListener log_listener_;
   bool detect_errors_in_javascript_;
 
   DISALLOW_COPY_AND_ASSIGN(WebRtcTestBase);