support multiple log message handlers in base/logging.h

base/test/mock_log.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 "base/test/mock_log.h"
 
 namespace base {
 namespace test {
 
 // static
@@ skipping 13 matching lines @@
   AutoLock scoped_lock(g_lock);
 
   // We don't use CHECK(), which can generate a new LOG message, and
   // thus can confuse MockLog objects or other registered
   // LogSinks.
   RAW_CHECK(!is_capturing_logs_);
   RAW_CHECK(!g_instance_);
 
   is_capturing_logs_ = true;
   g_instance_ = this;
-  previous_handler_ = logging::GetLogMessageHandler();
-  logging::SetLogMessageHandler(LogMessageHandler);
+  logging::AddLogMessageHandler(LogMessageHandler);
 }
 
 void MockLog::StopCapturingLogs() {
   AutoLock scoped_lock(g_lock);
 
   // We don't use CHECK(), which can generate a new LOG message, and
   // thus can confuse MockLog objects or other registered
   // LogSinks.
   RAW_CHECK(is_capturing_logs_);
   RAW_CHECK(g_instance_ == this);
 
   is_capturing_logs_ = false;
-  logging::SetLogMessageHandler(previous_handler_);
+  logging::RemoveLogMessageHandler(LogMessageHandler);
   g_instance_ = nullptr;
 }
 
 // static
 bool MockLog::LogMessageHandler(int severity,
-                                const char* file,
+                                const std::string& file,
                                 int line,
-                                size_t message_start,
                                 const std::string& str) {
   // gMock guarantees thread-safety for calling a mocked method
   // (https://github.com/google/googlemock/blob/master/googlemock/docs/CookBook.md#using-google-mock-and-threads)
   // but we also need to make sure that Start/StopCapturingLogs are synchronized
   // with LogMessageHandler.
   AutoLock scoped_lock(g_lock);
 
-  return g_instance_->Log(severity, file, line, message_start, str);
+  return g_instance_->Log(severity, file, line, str);
 }
 
 }  // namespace test
 }  // namespace base