Fixing a crash in our native messaging host binaries

remoting/host/native_messaging/log_message_handler.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 "remoting/host/native_messaging/log_message_handler.h"
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_util.h"
@@ skipping 107 matching lines @@
   std::string message = str.substr(message_start);
   base::TrimWhitespaceASCII(message, base::TRIM_ALL, &message);
 
   std::unique_ptr<base::DictionaryValue> dictionary(new base::DictionaryValue);
   dictionary->SetString("type", kDebugMessageTypeName);
   dictionary->SetString("severity", severity_string);
   dictionary->SetString("message", message);
   dictionary->SetString("file", file);
   dictionary->SetInteger("line", line);
 
+  // Protect against this instance being torn down after the delegate is run.
+  base::WeakPtr<LogMessageHandler> self = weak_ptr_factory_.GetWeakPtr();
   delegate_.Run(std::move(dictionary));
 
-  suppress_logging_ = false;
+  if (self) {
+    suppress_logging_ = false;
+  }
 }
 
 }  // namespace remoting