Add RawReceivePort to dart2js.

sdk/lib/_internal/lib/isolate_patch.dart

Index: sdk/lib/_internal/lib/isolate_patch.dart
diff --git a/sdk/lib/_internal/lib/isolate_patch.dart b/sdk/lib/_internal/lib/isolate_patch.dart
index 057e571d71664e3d2f9e0ddde4d828f5d1a77e76..a7911b723a6ae4ec00f6e360c6edc56977a1fee4 100644
--- a/sdk/lib/_internal/lib/isolate_patch.dart
+++ b/sdk/lib/_internal/lib/isolate_patch.dart
@@ -7,6 +7,8 @@
 import 'dart:_isolate_helper' show IsolateNatives,
                                    lazyPort,
                                    ReceivePortImpl,
+                                   RawReceivePortImpl,
+                                   ReceivePortWrapper,
                                    CloseToken,
                                    JsIsolateSink;
 
@@ -39,12 +41,12 @@ patch class ReceivePort {
   }
 
   patch factory ReceivePort.fromRawReceivePort(RawReceivePort rawPort) {
-    throw new UnimplementedError("ReceivePort.fromRawReceivePort");
+    return new ReceivePortWrapper(rawPort);
   }
 }
 
 patch class RawReceivePort {
   patch factory RawReceivePort([void handler(event)]) {
-    throw new UnimplementedError("RawReceivePort");
+    return new RawReceivePortImpl(handler);
   }
 }