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

components/crash/content/app/breakpad_mac.mm

Index: components/crash/content/app/breakpad_mac.mm
diff --git a/components/crash/content/app/breakpad_mac.mm b/components/crash/content/app/breakpad_mac.mm
index 6c6934bfa7ea832e707bcdbaef9ceab1cdf0ebff..163e0283e31c43828ddf6338066af8f2f7880c8f 100644
--- a/components/crash/content/app/breakpad_mac.mm
+++ b/components/crash/content/app/breakpad_mac.mm
@@ -73,8 +73,19 @@ void ClearCrashKeyValueImpl(const base::StringPiece& key) {
   }
 }
 
-bool FatalMessageHandler(int severity, const char* file, int line,
-                         size_t message_start, const std::string& str) {
+class FatalMessageHandler : logging::LogMessageHandler {
+  bool OnMessage(int severity,
+                 const char* file,
+                 int line,
+                 size_t message_start,
+                 const std::string& str) override;
+};
+
+bool FatalMessageHandler::OnMessage(int severity,
+                                    const char* file,
+                                    int line,
+                                    size_t message_start,
+                                    const std::string& str) {
   // Do not handle non-FATAL.
   if (severity != logging::LOG_FATAL)
     return false;
@@ -264,7 +275,10 @@ void InitCrashReporter(const std::string& process_type) {
   SetCrashKeyValue(@"prod", [info_dictionary objectForKey:@BREAKPAD_PRODUCT]);
   SetCrashKeyValue(@"plat", @"OS X");
 
-  logging::SetLogMessageHandler(&FatalMessageHandler);
+  // Intentionally leak the handler.
+  auto* log_handler = new FatalMessageHandler();
+  CHECK(log_handler);
+
   base::debug::SetDumpWithoutCrashingFunction(&DumpHelper::DumpWithoutCrashing);
 
   // abort() sends SIGABRT, which breakpad does not intercept.