Add a todo to ProcessUtils to use the new Java 9 APIs

PiperOrigin-RevId: 206573961
diff --git a/src/main/java/com/google/devtools/build/lib/util/ProcessUtils.java b/src/main/java/com/google/devtools/build/lib/util/ProcessUtils.java
index cbd69c1..964e019 100644
--- a/src/main/java/com/google/devtools/build/lib/util/ProcessUtils.java
+++ b/src/main/java/com/google/devtools/build/lib/util/ProcessUtils.java
@@ -44,6 +44,7 @@
    * @throws UnsatisfiedLinkError when JNI is not available.
    */
   public static int getpid() {
+    // TODO(ulfjack): Use ProcessHandle.current().getPid() here.
     if (OS.getCurrent() == OS.WINDOWS) {
       return WindowsProcesses.getpid();
     } else {