support multiple log message handlers in base/logging.h

chrome/test/chromedriver/logging.cc

Index: chrome/test/chromedriver/logging.cc
diff --git a/chrome/test/chromedriver/logging.cc b/chrome/test/chromedriver/logging.cc
index afd73754ca19963be1f6f74e75d15fdb070a88a6..815d5bc5e1f23f038dfa53d2114b53086565ac27 100644
--- a/chrome/test/chromedriver/logging.cc
+++ b/chrome/test/chromedriver/logging.cc
@@ -98,9 +98,8 @@ bool InternalIsVLogOn(int vlog_level) {
 }
 
 bool HandleLogMessage(int severity,
-                      const char* file,
+                      const std::string& file,
                       int line,
-                      size_t message_start,
                       const std::string& str) {
   Log::Level level = GetLevelFromSeverity(severity);
   std::string message = str.substr(message_start);
@@ -238,7 +237,7 @@ bool InitLogging() {
                        false,   // enable_thread_id
                        false,   // enable_timestamp
                        false);  // enable_tickcount
-  logging::SetLogMessageHandler(&HandleLogMessage);
+  logging::AddLogMessageHandler(&HandleLogMessage);
 
   logging::LoggingSettings logging_settings;
   logging_settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;