support multiple log message handlers in base/logging.h

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..327303daf140c29599b92a1063a429a36d091763 100644
--- a/remoting/host/logging_mac.cc
+++ b/remoting/host/logging_mac.cc
@@ -35,9 +35,8 @@ typedef base::ScopedGeneric<aslmsg, ScopedAslMsgTraits> ScopedAslMsg;
 // syslog -k Facility org.chromium.chromoting
 bool LogMessageToAsl(
     logging::LogSeverity severity,
-    const char* file,
+    const std::string& file,
     int line,
-    size_t message_start,
     const std::string& message) {
   int level;
   switch(severity) {
@@ -76,7 +75,7 @@ bool LogMessageToAsl(
     return false;
 
   if (asl_set(asl_message.get(), ASL_KEY_MSG,
-              message.c_str() + message_start) != 0)
+              message.c_str()) != 0)
     return false;
 
   asl_send(nullptr, asl_message.get());
@@ -94,7 +93,7 @@ void InitHostLogging() {
   logging::InitLogging(settings);
 
   // Write logs to syslog as well.
-  logging::SetLogMessageHandler(LogMessageToAsl);
+  logging::AddLogMessageHandler(LogMessageToAsl);
 }
 
 }  // namespace remoting