Revert "Revert "fix #27256, track type bounds for generic functions""

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// This library defines the operations that define and manipulate Dart
 /// classes.  Included in this are:
 ///   - Generics
 ///   - Class metadata
 ///   - Extension methods
 ///
@@ skipping 161 matching lines @@
           map.set(arg, value);
         }
       }
     }
     return value;
   }
   makeGenericType[$_genericTypeCtor] = $typeConstructor;
   return makeGenericType;
 })()''');
 
-getGenericClass(type) =>
-    JS('', '$safeGetOwnProperty($type, $_originalDeclaration)');
+getGenericClass(type) => safeGetOwnProperty(type, _originalDeclaration);
 
-getGenericArgs(type) => JS('', '$safeGetOwnProperty($type, $_typeArguments)');
+List getGenericArgs(type) =>
+    JS('List', '#', safeGetOwnProperty(type, _typeArguments));
 
 // TODO(vsm): Collapse into one expando.
 final _constructorSig = JS('', 'Symbol("sigCtor")');
 final _methodSig = JS('', 'Symbol("sigMethod")');
 final _fieldSig = JS('', 'Symbol("sigField")');
 final _getterSig = JS('', 'Symbol("sigGetter")');
 final _setterSig = JS('', 'Symbol("sigSetter")');
 final _staticSig = JS('', 'Symbol("sigStaticMethod")');
 final _staticFieldSig = JS('', 'Symbol("sigStaticField")');
 final _staticGetterSig = JS('', 'Symbol("sigStaticGetter")');
@@ skipping 474 matching lines @@
     '''(() => {
   let values = [];
   for (var i = 0; i < $names.length; i++) {
     let value = $const_(new $enumClass(i));
     values.push(value);
     Object.defineProperty($enumClass, $names[i],
         { value: value, configurable: true });
   }
   $enumClass.values = $constList(values, $enumClass);
 })()''');