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

base/logging_win.h

Index: base/logging_win.h
diff --git a/base/logging_win.h b/base/logging_win.h
index cdde7bb687cbbd524a0b5e412e0a2c6714b06f3f..3a042249376bc16fa159ac14a34b96e332ee9cbc 100644
--- a/base/logging_win.h
+++ b/base/logging_win.h
@@ -7,6 +7,7 @@
 
 #include <stddef.h>
 
+#include <memory>
 #include <string>
 
 #include "base/base_export.h"
@@ -57,9 +58,6 @@ class BASE_EXPORT LogEventProvider : public base::win::EtwTraceProvider {
  public:
   static LogEventProvider* GetInstance();
 
-  static bool LogMessage(logging::LogSeverity severity, const char* file,
-      int line, size_t message_start, const std::string& str);
-
   static void Initialize(const GUID& provider_name);
   static void Uninitialize();
 
@@ -70,7 +68,17 @@ class BASE_EXPORT LogEventProvider : public base::win::EtwTraceProvider {
 
  private:
   LogEventProvider();
-
+  ~LogEventProvider() override;
+
+  class WinLogMessageListener : LogMessageListener {
+   public:
+    void OnMessage(logging::LogSeverity severity,
+                   const char* file,
+                   int line,
+                   size_t message_start,
+                   const std::string& str) override;
+  };
+  std::unique_ptr<WinLogMessageListener> log_listener_;
   // The log severity prior to OnEventsEnabled,
   // restored in OnEventsDisabled.
   logging::LogSeverity old_log_level_;