First cut at _spawnUri rpc in the vm service.

runtime/lib/vmservice.cc

Index: runtime/lib/vmservice.cc
diff --git a/runtime/lib/vmservice.cc b/runtime/lib/vmservice.cc
index 831b9b8dae14210bec8d63aa97671237fb9a2776..9d2d82442e8a1a06388070cece149d85c9eb73ae 100644
--- a/runtime/lib/vmservice.cc
+++ b/runtime/lib/vmservice.cc
@@ -13,6 +13,7 @@
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/port.h"
+#include "vm/service_event.h"
 #include "vm/service_isolate.h"
 #include "vm/symbols.h"
 
@@ -450,4 +451,39 @@ DEFINE_NATIVE_ENTRY(VMService_DecodeAssets, 1) {
 #endif
 }
 
+
+
+DEFINE_NATIVE_ENTRY(VMService_spawnUriNotify, 2) {
+  GET_NON_NULL_NATIVE_ARGUMENT(Instance, result, arguments->NativeArgAt(0));
+  GET_NON_NULL_NATIVE_ARGUMENT(String, token, arguments->NativeArgAt(1));
+
+  if (result.IsSendPort()) {
+    Dart_Port id = SendPort::Cast(result).Id();
+    Isolate* isolate = PortMap::GetIsolate(id);
+    if (isolate != NULL) {
+      ServiceEvent spawn_event(isolate, ServiceEvent::kIsolateSpawn);
+      spawn_event.set_spawn_token(&token);
+      Service::HandleEvent(&spawn_event);
+    } else {
+      // There is no isolate at the control port anymore.  Must have
+      // died already.
+      ServiceEvent spawn_event(NULL, ServiceEvent::kIsolateSpawn);
+      const String& error = String::Handle(String::New(
+          "spawned isolate exited before notification completed"));
+      spawn_event.set_spawn_token(&token);
+      spawn_event.set_spawn_error(&error);
+      Service::HandleEvent(&spawn_event);
+    }
+  } else {
+    // The isolate failed to spawn.
+    ASSERT(result.IsString());
+    ServiceEvent spawn_event(NULL, ServiceEvent::kIsolateSpawn);
+    spawn_event.set_spawn_token(&token);
+    spawn_event.set_spawn_error(&String::Cast(result));
+    Service::HandleEvent(&spawn_event);
+  }
+
+  return Object::null();
+}
+
 }  // namespace dart