Merge remote repo native into ext/native/.

ext/native/thread/executor.cpp

@@ -0,0 +1,10 @@
+#include "thread/executor.h"
+#include "base/functional.h"
+
+namespace threading {
+
+void SameThreadExecutor::Run(std::function<void()> func) {
+  func();
+}
+
+}  // namespace threading