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

remoting/host/logging_mac.cc

Index: remoting/host/logging_mac.cc
diff --git a/remoting/host/logging_mac.cc b/remoting/host/logging_mac.cc
index 39e007d409b528d5fe9b38307afe9ebc84dd8d94..ae6870c728334553ee03107304c4da3ad988e044 100644
--- a/remoting/host/logging_mac.cc
+++ b/remoting/host/logging_mac.cc
@@ -33,12 +33,19 @@ typedef base::ScopedGeneric<aslmsg, ScopedAslMsgTraits> ScopedAslMsg;
 // Logging message handler that writes to syslog.
 // The log can be obtained by running the following in a terminal:
 // syslog -k Facility org.chromium.chromoting
-bool LogMessageToAsl(
-    logging::LogSeverity severity,
-    const char* file,
-    int line,
-    size_t message_start,
-    const std::string& message) {
+class LogMessageListener : logging::LogMessageListener {
+  void OnMessage(logging::LogSeverity severity,
+                 const char* file,
+                 int line,
+                 size_t message_start,
+                 const std::string& message) override;
+};
+
+void LogMessageListener::OnMessage(logging::LogSeverity severity,
+                                   const char* file,
+                                   int line,
+                                   size_t message_start,
+                                   const std::string& message) {
   int level;
   switch(severity) {
     case logging::LOG_INFO:
@@ -60,29 +67,28 @@ bool LogMessageToAsl(
 
   ScopedAslMsg asl_message(asl_new(ASL_TYPE_MSG));
   if (!asl_message.is_valid())
-    return false;
+    return;
 
   if (asl_set(asl_message.get(), ASL_KEY_FACILITY,
               kChromotingLoggingFacility) != 0)
-    return false;
+    return;
 
   if (asl_set(asl_message.get(), ASL_KEY_LEVEL,
               base::IntToString(level).c_str()) != 0)
-    return false;
+    return;
 
   // Restrict read access to the message to root and the current user.
   if (asl_set(asl_message.get(), ASL_KEY_READ_UID,
               base::IntToString(geteuid()).c_str()) != 0)
-    return false;
+    return;
 
   if (asl_set(asl_message.get(), ASL_KEY_MSG,
               message.c_str() + message_start) != 0)
-    return false;
+    return;
 
   asl_send(nullptr, asl_message.get());
 
   // Don't prevent message from being logged by traditional means.
-  return false;
 }
 
 }  // namespace
@@ -94,7 +100,9 @@ void InitHostLogging() {
   logging::InitLogging(settings);
 
   // Write logs to syslog as well.
-  logging::SetLogMessageHandler(LogMessageToAsl);
+  // Intentionally leak the listener
+  auto* listener = new LogMessageListener();
+  CHECK(listener);
 }
 
 }  // namespace remoting