Implement a simple ThreadChecker for Mojo and add to |internal::SharedData| and |internal::Router|.

third_party/mojo/src/mojo/public/cpp/bindings/lib/thread_checker_posix.h

Index: third_party/mojo/src/mojo/public/cpp/bindings/lib/thread_checker_posix.h
diff --git a/third_party/mojo/src/mojo/public/cpp/bindings/lib/thread_checker_posix.h b/third_party/mojo/src/mojo/public/cpp/bindings/lib/thread_checker_posix.h
new file mode 100644
index 0000000000000000000000000000000000000000..4701b8898efe9ffc1fd443fe1acb2b57e8c8f672
--- /dev/null
+++ b/third_party/mojo/src/mojo/public/cpp/bindings/lib/thread_checker_posix.h
@@ -0,0 +1,31 @@
+// 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.
+
+#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_THREAD_CHECKER_POSIX_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_LIB_THREAD_CHECKER_POSIX_H_
+
+#include <pthread.h>
+
+#include "mojo/public/cpp/system/macros.h"
+
+namespace mojo {
+namespace internal {
+
+// An implementation of ThreadChecker for POSIX systems.
+class ThreadCheckerPosix {
+ public:
+  ThreadCheckerPosix();
+  ~ThreadCheckerPosix();
+
+  bool CalledOnValidThread() const MOJO_WARN_UNUSED_RESULT;
+ private:
+  const pthread_t attached_thread_id_;
+
+  MOJO_DISALLOW_COPY_AND_ASSIGN(ThreadCheckerPosix);
+};
+
+}  // namespace internal
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_THREAD_CHECKER_POSIX_H_