- Implement Isolate.ping.

runtime/lib/isolate_patch.dart

Index: runtime/lib/isolate_patch.dart
===================================================================
--- runtime/lib/isolate_patch.dart	(revision 42173)
+++ runtime/lib/isolate_patch.dart	(working copy)
@@ -322,7 +322,9 @@
   // in vm/isolate.cc.
   static const _PAUSE = 1;
   static const _RESUME = 2;
+  static const _PING = 3;
 
+
   static SendPort _spawnFunction(SendPort readyPort, Function topLevelFunction,
                                  var message)
       native "Isolate_spawnFunction";
@@ -369,7 +371,12 @@
   }
 
   /* patch */ void ping(SendPort responsePort, [int pingType = IMMEDIATE]) {
-    throw new UnsupportedError("ping");
+    var msg = new List(4)
+        ..[0] = 0  // Make room for OOM message type.
+        ..[1] = _PING
+        ..[2] = responsePort
+        ..[3] = pingType;
+    _sendOOB(controlPort, msg);
   }
 
   /* patch */ void addErrorListener(SendPort port) {