Let the process have more than one thread under ThreadSanitizer in RenderSandboxHostLinux::Init

content/browser/renderer_host/render_sandbox_host_linux.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_sandbox_host_linux.h"
 
 #include <fcntl.h>
 #include <fontconfig/fontconfig.h>
 #include <stdint.h>
 #include <sys/poll.h>
@@ skipping 691 matching lines @@
 
   renderer_socket_ = fds[0];
   const int browser_socket = fds[1];
 
   int pipefds[2];
   CHECK(0 == pipe(pipefds));
   const int child_lifeline_fd = pipefds[0];
   childs_lifeline_fd_ = pipefds[1];
 
   // We need to be monothreaded before we fork().
-#if !defined(TOOLKIT_GTK)
+#if !defined(TOOLKIT_GTK) && !defined(THREAD_SANITIZER)
   // Exclude gtk port as TestSuite in base/tests/test_suite.cc is calling
   // gtk_init.
-  // TODO(oshima): Remove ifdef when above issues are resolved.
+  // TODO(oshima): Remove the TOOLKIT_GTK ifdef when above issues are resolved.
+  // ThreadSanitizer spawns its own background thread.
   DCHECK_EQ(1, base::GetNumberOfThreads(base::GetCurrentProcessHandle()));
 #endif
   pid_ = fork();
   if (pid_ == 0) {
     if (IGNORE_EINTR(close(fds[0])) < 0)
       DPLOG(ERROR) << "close";
     if (IGNORE_EINTR(close(pipefds[1])) < 0)
       DPLOG(ERROR) << "close";
 
     SandboxIPCProcess handler(child_lifeline_fd, browser_socket, sandbox_path);
     handler.Run();
     _exit(0);
   }
 }
 
 RenderSandboxHostLinux::~RenderSandboxHostLinux() {
   if (initialized_) {
     if (IGNORE_EINTR(close(renderer_socket_)) < 0)
       PLOG(ERROR) << "close";
     if (IGNORE_EINTR(close(childs_lifeline_fd_)) < 0)
       PLOG(ERROR) << "close";
   }
 }
 
 }  // namespace content