Register generic type of instantiated Map literal.

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
index 037ea46416e47a58029204bdc65fe2054a9a9e5d..282a2ed828e7eb22a0654cec191916b80741f464 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
@@ -796,6 +796,9 @@ class JavaScriptBackend extends Backend {
         // of the map.
         enqueueClass(enqueuer, compiler.listClass, elements);
         enqueueClass(enqueuer, mapLiteralClass, elements);
+        // For map literals, the dependency between the implementation class
+        // and [Map] is not visible, so we have to add it manually.
+        rti.registerRtiDependency(mapLiteralClass, cls);
         enqueueInResolution(getMapMaker(), elements);
       } else if (cls == compiler.boundClosureClass) {
         // TODO(ngeoffray): Move the bound closure class in the