Implement type argument access and reification of runtime types.

pkg/compiler/lib/src/js_backend/codegen/glue.dart

Index: pkg/compiler/lib/src/js_backend/codegen/glue.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen/glue.dart b/pkg/compiler/lib/src/js_backend/codegen/glue.dart
index ebe89235e47e972b9ba14148d6c782c38d365f1d..712e90a69c22bdf99d18b449b5aab110efc109d5 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/glue.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/glue.dart
@@ -11,6 +11,7 @@ import '../../js/js.dart' as js;
 import '../../constants/values.dart';
 import '../../elements/elements.dart';
 import '../../constants/expressions.dart';
+import '../../dart_types.dart' show TypeVariableType;
 
 /// Encapsulates the dependencies of the function-compiler to the compiler,
 /// backend and emitter.
@@ -115,4 +116,38 @@ class Glue {
     return new js.VariableUse(
         _backend.namer.globalObjectFor(_backend.interceptorsLibrary));
   }
+
+  FunctionElement getCreateRuntimeType() {
+    return _backend.getCreateRuntimeType();
+  }
+
+  FunctionElement getRuntimeTypeToString() {
+    return _backend.getRuntimeTypeToString();
+  }
+
+  FunctionElement getTypeArgumentWithSubstitution() {
+    return _backend.getGetRuntimeTypeArgument();
+  }
+
+  FunctionElement getTypeArgumentByIndex() {
+    return _backend.getGetTypeArgumentByIndex();
+  }
+
+  js.Expression getSubstitutionName(ClassElement cls) {
+    return js.string(_namer.substitutionName(cls));
+  }
+
+  int getTypeVariableIndex(TypeVariableType variable) {
+    return RuntimeTypes.getTypeVariableIndex(variable.element);
+  }
+
+  bool needsSubstitutionForTypeVariableAccess(ClassElement cls) {
+    ClassWorld classWorld = _compiler.world;
+    if (classWorld.isUsedAsMixin(cls)) return true;
+
+    Iterable<ClassElement> subclasses = _compiler.world.strictSubclassesOf(cls);
+    return subclasses.any((ClassElement subclass) {
+      return !_backend.rti.isTrivialSubstitution(subclass, cls);
+    });
+  }
 }