emit interfaces before use

lib/src/codegen/js_codegen.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.
 
 library dev_compiler.src.codegen.js_codegen;
 
 import 'dart:collection' show HashSet, HashMap;
 import 'dart:io' show Directory, File;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
@@ skipping 354 matching lines @@
 
     if (classElem.type.isObject) return body;
 
     // If we're not lazy, we still need to ensure our dependencies are
     // generated first.
     var classDefs = <JS.Statement>[];
     _emitClassIfNeeded(classDefs, classElem.supertype.element);
     for (var m in classElem.mixins) {
       _emitClassIfNeeded(classDefs, m.element);
     }
+    for (var i in classElem.interfaces) {
+      _emitClassIfNeeded(classDefs, i.element);
+    }
     classDefs.add(body);
     return _statement(classDefs);
   }
 
   void _emitClassIfNeeded(List<JS.Statement> defs, ClassElement base) {
     // We can only emit classes from this library.
     if (base.library != currentLibrary) return;
 
     var baseNode = _pendingClasses[base];
     if (baseNode != null) defs.add(visitClassDeclaration(baseNode));
   }
 
   /// Returns true if the supertype or mixins aren't loaded.
   /// If that is the case, we'll emit a lazy class definition.
   bool _lazyClass(ClassElement cls) {
     if (cls.type.isObject) return false;
 
     assert(cls.library == currentLibrary);
     var result = _lazyClassMemo[cls];
     if (result != null) return result;
 
     result = _classMightNotBeLoaded(cls.supertype.element);
     for (var mixin in cls.mixins) {
       if (result) break;
       result = _classMightNotBeLoaded(mixin.element);
     }
+    for (var iface in cls.interfaces) {
+      if (result) break;
+      result = _classMightNotBeLoaded(iface.element);
+    }
     return _lazyClassMemo[cls] = result;
   }
 
   /// Curated order to minimize lazy classes needed by dart:core and its
   /// transitive SDK imports.
   static const CORELIB_ORDER = const [
     'dart.core',
     'dart.collection',
     'dart._internal'
   ];
@@ skipping 1967 matching lines @@
 
     // TODO(jmesserly): in many cases marking the end will be unncessary.
     printer.mark(_location(node.end));
   }
 
   String _getIdentifier(AstNode node) {
     if (node is SimpleIdentifier) return node.name;
     return null;
   }
 }