Introduce ClassLike, MemberLike, FieldLike and FunctionLike

pkg/compiler/lib/src/js_backend/namer.dart

Index: pkg/compiler/lib/src/js_backend/namer.dart
diff --git a/pkg/compiler/lib/src/js_backend/namer.dart b/pkg/compiler/lib/src/js_backend/namer.dart
index 804386115e84b174ddc1f1187a12f06840e990e3..a528722e52d6fc6b475dab77f976f1ea119c7744 100644
--- a/pkg/compiler/lib/src/js_backend/namer.dart
+++ b/pkg/compiler/lib/src/js_backend/namer.dart
@@ -667,7 +667,7 @@ class Namer {
   }
 
   /// Annotated name for [method] encoding arity and named parameters.
-  jsAst.Name instanceMethodName(FunctionElement method) {
+  jsAst.Name instanceMethodName(MethodElement method) {
     if (method.isGenerativeConstructorBody) {
       return constructorBodyName(method);
     }
@@ -1250,7 +1250,7 @@ class Namer {
     return disambiguated;
   }
 
-  String suffixForGetInterceptor(Iterable<ClassElement> classes) {
+  String suffixForGetInterceptor(Iterable<ClassLike> classes) {
     String abbreviate(ClassElement cls) {
       if (cls == coreClasses.objectClass) return "o";
       if (cls == helpers.jsStringClass) return "s";
@@ -1279,7 +1279,7 @@ class Namer {
   }
 
   /// Property name used for `getInterceptor` or one of its specializations.
-  jsAst.Name nameForGetInterceptor(Iterable<ClassElement> classes) {
+  jsAst.Name nameForGetInterceptor(Iterable<ClassLike> classes) {
     FunctionElement getInterceptor = helpers.getInterceptorMethod;
     if (classes.contains(helpers.jsInterceptorClass)) {
       // If the base Interceptor class is in the set of intercepted classes, we