Add access to process id for both current process and processes started

sdk/lib/io/process.dart

Index: sdk/lib/io/process.dart
diff --git a/sdk/lib/io/process.dart b/sdk/lib/io/process.dart
index fc2a4aa7d455d0f9ebfe170230edc244eb8fc5d4..fd61c56e5145ab8c4a279962bd10b59df84e8fd5 100644
--- a/sdk/lib/io/process.dart
+++ b/sdk/lib/io/process.dart
@@ -10,6 +10,7 @@ class _ProcessUtils {
   external static _exit(int status);
   external static _setExitCode(int status);
   external static _sleep(int millis);
+  external static int _pid(Process process);
 }
 
 /**
@@ -54,6 +55,11 @@ void sleep(Duration duration) {
 }
 
 /**
+ * Returns the PID if the current process.

[Anders Johnsen, 2013/04/17 09:13:06]

Move to Process.currentPid static getter?

[Søren Gjesse, 2013/04/17 10:15:12]

I think the top level getter fits with the top level exitCode setter.

+ */
+int get pid => _ProcessUtils._pid(null);
+
+/**
  * [Process] is used to start new processes using the static
  * [start] and [run] methods.
  */
@@ -118,6 +124,11 @@ abstract class Process {
   IOSink get stdin;
 
   /**
+   * Returns the process id of the process.
+   */
+  int get pid;
+
+  /**
    * Returns a [:Future:] which completes with the exit code of the process
    * when the process completes.
    *
@@ -162,6 +173,11 @@ abstract class ProcessResult {
    * Standard error from the process as a string.
    */
   String get stderr;
+
+  /**
+   * Process id from the process.
+   */
+  int get pid;
 }