fixes browser/runtime_test, and a few extension member fixes

lib/src/codegen/js_codegen.dart

Index: lib/src/codegen/js_codegen.dart
diff --git a/lib/src/codegen/js_codegen.dart b/lib/src/codegen/js_codegen.dart
index f89564d9eaa16176e00d5161f22de7f2b3f3b6f6..632e8c18a98052dac7b4ec61c4df4a230412fdca 100644
--- a/lib/src/codegen/js_codegen.dart
+++ b/lib/src/codegen/js_codegen.dart
@@ -558,21 +558,6 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
         new JS.ArrayInitializer(
             classElem.interfaces.map(_emitTypeName).toList())
       ]));
-
-      // If a concrete class implements one of our extensions, we might need to
-      // add forwarders.
-      var extensions = _extensionsToImplement(classElem);
-      if (extensions.isNotEmpty) {
-        var methodNames = [];
-        for (var e in extensions) {
-          methodNames.add(_emitMemberDeclarationName(e));
-        }
-        body.add(js.statement('dart.defineExtensionMembers(#, #);', [
-          name,
-          new JS.ArrayInitializer(methodNames,
-              multiline: methodNames.length > 4)
-        ]));
-      }
     }
 
     // Named constructors
@@ -608,7 +593,7 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
               classElem.lookUpInheritedConcreteMethod(name, currentLibrary);
           if (inheritedElement != null &&
               inheritedElement.type == element.type) continue;
-          var memberName = _emitMemberDeclarationName(element);
+          var memberName = _elementMemberName(element);
           var parts =
               _emitFunctionTypeParts(element.type, dynamicIsBottom: false);
           var property =
@@ -655,6 +640,20 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
       }
     }
 
+    // If a concrete class implements one of our extensions, we might need to
+    // add forwarders.
+    var extensions = _extensionsToImplement(classElem);
+    if (extensions.isNotEmpty) {
+      var methodNames = [];
+      for (var e in extensions) {
+        methodNames.add(_elementMemberName(e, declaration: true));
+      }
+      body.add(js.statement('dart.defineExtensionMembers(#, #);', [
+        name,
+        new JS.ArrayInitializer(methodNames, multiline: methodNames.length > 4)
+      ]));
+    }
+
     return _statement(body);
   }
 
@@ -1048,7 +1047,7 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
     var params = _visit(node.parameters);
     if (params == null) params = [];
 
-    return new JS.Method(_emitMemberDeclarationName(node.element),
+    return new JS.Method(_elementMemberName(node.element, declaration: true),
         new JS.Fun(params, _visit(node.body)),
         isGetter: node.isGetter,
         isSetter: node.isSetter,
@@ -2524,7 +2523,8 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
   ///
   /// Unlike call sites, we always have an element available, so we can use it
   /// directly rather than computing the relevant options for [_emitMemberName].
-  JS.Expression _emitMemberDeclarationName(ExecutableElement e) {
+  JS.Expression _elementMemberName(ExecutableElement e,
+      {bool declaration: false}) {
     String name;
     if (e is PropertyAccessorElement) {
       name = e.variable.name;
@@ -2535,7 +2535,7 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
         type: (e.enclosingElement as ClassElement).type,
         unary: e.parameters.isEmpty,
         isStatic: e.isStatic,
-        declaration: true);
+        declaration: declaration);
   }
 
   /// This handles member renaming for private names and operators.
@@ -2599,9 +2599,10 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
     }
 
     // Dart "extension" methods. Used for JS Array, Boolean, Number, String.
-    if (!declaration && _extensionTypes.contains(type.element)) {
-      // Special case `length`. We can call it directly.
-      if (name != 'length') return js.call('dartx.#', _propertyName(name));
+    // Special case `length`. We can call it directly.
+    if (_extensionTypes.contains(type.element) && name != 'length') {
+      var code = declaration ? 'dart.extensionMember(#)' : 'dartx.#';
+      return js.call(code, _propertyName(name));
     }
 
     return _propertyName(name);