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

remoting/host/native_messaging/log_message_handler.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/native_messaging/log_message_handler.h"
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_util.h"
@@ skipping 19 matching lines @@
     const Delegate& delegate)
     : delegate_(delegate),
       suppress_logging_(false),
       caller_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       weak_ptr_factory_(this) {
   base::AutoLock lock(g_log_message_handler_lock.Get());
   if (g_log_message_handler) {
     LOG(FATAL) << "LogMessageHandler is already registered. Only one instance "
                << "per process is allowed.";
   }
-  previous_log_message_handler_ = logging::GetLogMessageHandler();
-  logging::SetLogMessageHandler(&LogMessageHandler::OnLogMessage);
   g_log_message_handler = this;
 }
 
 LogMessageHandler::~LogMessageHandler() {
   base::AutoLock lock(g_log_message_handler_lock.Get());
-  if (logging::GetLogMessageHandler() != &LogMessageHandler::OnLogMessage) {
-    LOG(FATAL) << "LogMessageHandler is not the top-most message handler. "
-               << "Cannot unregister.";
-  }
-  logging::SetLogMessageHandler(previous_log_message_handler_);
   g_log_message_handler = nullptr;
 }
 
 // static
 const char* LogMessageHandler::kDebugMessageTypeName = "_debug_log";
 
-// static
-bool LogMessageHandler::OnLogMessage(
-    logging::LogSeverity severity,
-    const char* file,
-    int line,
-    size_t message_start,
-    const std::string& str) {
+bool LogMessageHandler::OnMessage(logging::LogSeverity severity,
+                                  const char* file,
+                                  int line,
+                                  size_t message_start,
+                                  const std::string& str) {
   base::AutoLock lock(g_log_message_handler_lock.Get());
   if (g_log_message_handler) {
     g_log_message_handler->PostLogMessageToCorrectThread(
         severity, file, line, message_start, str);
   }
   return false;
 }
 
 void LogMessageHandler::PostLogMessageToCorrectThread(
     logging::LogSeverity severity,
@@ skipping 49 matching lines @@
   dictionary->SetString("message", message);
   dictionary->SetString("file", file);
   dictionary->SetInteger("line", line);
 
   delegate_.Run(std::move(dictionary));
 
   suppress_logging_ = false;
 }
 
 }  // namespace remoting