TSANv2: disable non sandbox-related threading checks under TSAN.

content/browser/renderer_host/render_sandbox_host_linux.cc

Index: content/browser/renderer_host/render_sandbox_host_linux.cc
diff --git a/content/browser/renderer_host/render_sandbox_host_linux.cc b/content/browser/renderer_host/render_sandbox_host_linux.cc
index 19cbc5b4b351e41df3ab31607d21e9dc9f00cba4..7de2947e2941be2af5499cb33226e1c6014cf6ec 100644
--- a/content/browser/renderer_host/render_sandbox_host_linux.cc
+++ b/content/browser/renderer_host/render_sandbox_host_linux.cc
@@ -709,12 +709,12 @@ void RenderSandboxHostLinux::Init(const std::string& sandbox_path) {
   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.
   DCHECK_EQ(1, base::GetNumberOfThreads(base::GetCurrentProcessHandle()));
-#endif
+#endif  // !defined(TOOLKIT_GTK) && !defined(THREAD_SANITIZER)
   pid_ = fork();
   if (pid_ == 0) {
     if (IGNORE_EINTR(close(fds[0])) < 0)