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

base/logging_win.cc

Index: base/logging_win.cc
diff --git a/base/logging_win.cc b/base/logging_win.cc
index 319ae8a9d38186aa7ffc6466f574c2a795a1832c..92035e00e5ea52e073d525901a8f1d55900c8218 100644
--- a/base/logging_win.cc
+++ b/base/logging_win.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/logging_win.h"
+#include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
 #include <initguid.h>  // NOLINT
 
@@ -14,6 +15,9 @@ using base::win::EtwMofEvent;
 DEFINE_GUID(kLogEventId,
     0x7fe69228, 0x633e, 0x4f06, 0x80, 0xc1, 0x52, 0x7f, 0xea, 0x23, 0xe3, 0xa7);
 
+LogEventProvider::WinLogMessageHandler* LogEventProvider::log_handler_ =

[grt (UTC plus 2), 2016/08/15 07:36:32]

nit:
// static
just before this

[wychen, 2016/08/17 17:08:54]

No longer static.

+    nullptr;
+
 LogEventProvider::LogEventProvider() : old_log_level_(LOG_NONE) {
 }
 
@@ -22,8 +26,11 @@ LogEventProvider* LogEventProvider::GetInstance() {
                                                LogEventProvider>>::get();
 }
 
-bool LogEventProvider::LogMessage(logging::LogSeverity severity,
-    const char* file, int line, size_t message_start,
+bool LogEventProvider::WinLogMessageHandler::OnMessage(
+    logging::LogSeverity severity,
+    const char* file,
+    int line,
+    size_t message_start,
     const std::string& message) {
   EtwEventLevel level = TRACE_LEVEL_NONE;
 
@@ -88,7 +95,8 @@ bool LogEventProvider::LogMessage(logging::LogSeverity severity,
     provider->Log(event.get());
   }
 
-  // Don't increase verbosity in other log destinations.
+  // Don't increase verbosity in other log destinations below this handler
+  // in the handler stack.
   if (severity < provider->old_log_level_)
     return true;
 
@@ -102,11 +110,13 @@ void LogEventProvider::Initialize(const GUID& provider_name) {
   provider->Register();
 
   // Register our message handler with logging.
-  SetLogMessageHandler(LogMessage);
+  log_handler_ = new WinLogMessageHandler();

[grt (UTC plus 2), 2016/08/15 07:36:32]

  DCHECK_EQ(nullptr, log_handler_);

[wychen, 2016/08/17 17:08:54]

Used unique_ptr.

 }
 
 void LogEventProvider::Uninitialize() {
   LogEventProvider::GetInstance()->Unregister();
+  delete log_handler_;

[grt (UTC plus 2), 2016/08/15 07:36:32]

  DCHECK_NE(nullptr, log_handler_);

[wychen, 2016/08/17 17:08:54]

Used unique_ptr.

+  log_handler_ = nullptr;
 }
 
 void LogEventProvider::OnEventsEnabled() {