support multiple log message handlers in base/logging.h

remoting/client/plugin/chromoting_instance.cc

Index: remoting/client/plugin/chromoting_instance.cc
diff --git a/remoting/client/plugin/chromoting_instance.cc b/remoting/client/plugin/chromoting_instance.cc
index 1fa13ebd3a45516d7e2f7fc4beb7bff89830d8a3..4d83850240c453a1e61a4cf7c400ee5e88877614 100644
--- a/remoting/client/plugin/chromoting_instance.cc
+++ b/remoting/client/plugin/chromoting_instance.cc
@@ -1043,7 +1043,7 @@ void ChromotingInstance::RegisterLogMessageHandler() {
 
   // Set up log message handler.
   // This is not thread-safe so we need it within our lock.
-  logging::SetLogMessageHandler(&LogToUI);
+  logging::AddLogMessageHandler(&LogToUI);
 }
 
 void ChromotingInstance::RegisterLoggingInstance() {
@@ -1063,9 +1063,8 @@ void ChromotingInstance::UnregisterLoggingInstance() {
 }
 
 // static
-bool ChromotingInstance::LogToUI(int severity, const char* file, int line,
-                                 size_t message_start,
-                                 const std::string& str) {
+bool ChromotingInstance::LogToUI(int severity, const std::string& file,
+                                 int line, const std::string& str) {
   PP_LogLevel log_level = PP_LOGLEVEL_ERROR;
   switch (severity) {
     case logging::LOG_INFO: