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

remoting/host/native_messaging/log_message_handler.cc

Index: remoting/host/native_messaging/log_message_handler.cc
diff --git a/remoting/host/native_messaging/log_message_handler.cc b/remoting/host/native_messaging/log_message_handler.cc
index e2e3cd8b58c67d9c116d172610dba878b52c5fdf..756542e403e167c3030f3a99b6ff74140e115cfd 100644
--- a/remoting/host/native_messaging/log_message_handler.cc
+++ b/remoting/host/native_messaging/log_message_handler.cc
@@ -36,18 +36,17 @@ LogMessageHandler::LogMessageHandler(
     LOG(FATAL) << "LogMessageHandler is already registered. Only one instance "
                << "per process is allowed.";
   }
-  previous_log_message_handler_ = logging::GetLogMessageHandler();
-  logging::SetLogMessageHandler(&LogMessageHandler::OnLogMessage);
+  logging::PushLogMessageHandler(&LogMessageHandler::OnLogMessage);
   g_log_message_handler = this;
 }
 
 LogMessageHandler::~LogMessageHandler() {
   base::AutoLock lock(g_log_message_handler_lock.Get());
-  if (logging::GetLogMessageHandler() != &LogMessageHandler::OnLogMessage) {
+  if (logging::GetTopLogMessageHandler() != &LogMessageHandler::OnLogMessage) {
     LOG(FATAL) << "LogMessageHandler is not the top-most message handler. "
                << "Cannot unregister.";
   }

[Dan Beam, 2016/07/15 03:11:19]

^ do we still need this?

[wychen, 2016/07/18 15:44:12]

Cleaned this up to simplify logic.

-  logging::SetLogMessageHandler(previous_log_message_handler_);
+  logging::PopLogMessageHandler(&LogMessageHandler::OnLogMessage);
   g_log_message_handler = nullptr;
 }