Make event-handlers edge-triggered and move socket-state to Dart.

runtime/bin/dartutils.cc

Index: runtime/bin/dartutils.cc
diff --git a/runtime/bin/dartutils.cc b/runtime/bin/dartutils.cc
index 2b8e495799a703c1edded2fbda2b5c4fbde97667..8bc5aeab8e55a25a32adbbcba6b5af6930de52cf 100644
--- a/runtime/bin/dartutils.cc
+++ b/runtime/bin/dartutils.cc
@@ -811,6 +811,15 @@ bool DartUtils::PostInt32(Dart_Port port_id, int32_t value) {
 }
 
 
+bool DartUtils::PostInt64(Dart_Port port_id, int64_t value) {
+  // Post a message with the integer value.
+  Dart_CObject object;
+  object.type = Dart_CObject_kInt64;
+  object.value.as_int64 = value;
+  return Dart_PostCObject(port_id, &object);
+}
+
+
 Dart_Handle DartUtils::GetDartType(const char* library_url,
                                    const char* class_name) {
   return Dart_GetType(Dart_LookupLibrary(NewString(library_url)),