pkg/compiler: fix imports

pkg/compiler/lib/src/use_unused_api.dart

 // Copyright (c) 2012, 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 file use methods that aren't used by dart2js.dart, but that we wish to
 /// keep anyway. This might be general API that isn't currently in use,
 /// debugging aids, or API only used for testing (see TODO below).
 
 library dart2js.use_unused_api;
 
 import '../compiler.dart' as api;
-
 import 'colors.dart' as colors;
 import 'compiler.dart' as compiler;
 import 'constants/constant_system.dart' as constants;
 import 'constants/constructors.dart' as constants;
 import 'constants/evaluation.dart' as constants;
 import 'constants/expressions.dart' as constants;
 import 'constants/values.dart' as constants;
 import 'cps_ir/cps_ir_builder.dart' as ir_builder;
 import 'cps_ir/cps_ir_builder_task.dart' as ir_builder;
-import 'tree_ir/tree_ir_nodes.dart' as tree_ir;
+import 'dart2js.dart' as dart2js;
 import 'dart_types.dart' as dart_types;
-import 'dart2js.dart' as dart2js;
 import 'deferred_load.dart' as deferred;
 import 'diagnostics/source_span.dart' as diagnostics;
 import 'elements/elements.dart' as elements;
 import 'elements/modelx.dart' as modelx;
 import 'elements/visitor.dart' as elements_visitor;
 import 'filenames.dart' as filenames;
 import 'inferrer/type_graph_inferrer.dart' as type_graph_inferrer;
 import 'io/line_column_provider.dart' as io;
 import 'io/source_map_builder.dart' as io;
 import 'js/js.dart' as js;
 import 'js_backend/js_backend.dart' as js_backend;
+import 'js_emitter/full_emitter/emitter.dart' as full;
 import 'js_emitter/js_emitter.dart' as js_emitter;
-import 'js_emitter/full_emitter/emitter.dart' as full;
 import 'js_emitter/program_builder/program_builder.dart' as program_builder;
+import 'parser/partial_elements.dart'
+    show PartialClassElement, PartialFunctionElement;
+import 'resolution/operators.dart' as operators;
 import 'resolution/semantic_visitor.dart' as semantic_visitor;
-import 'resolution/operators.dart' as operators;
 import 'script.dart';
 import 'source_file_provider.dart' as source_file_provider;
 import 'ssa/nodes.dart' as ssa;
 import 'tree/tree.dart' as tree;
+import 'tree_ir/tree_ir_nodes.dart' as tree_ir;
 import 'util/util.dart' as util;
 import 'world.dart';
 
-import 'parser/partial_elements.dart'
-    show PartialClassElement, PartialFunctionElement;
-
 class ElementVisitor extends elements_visitor.BaseElementVisitor {
   visitElement(e, a) {}
 }
 
 void main(List<String> arguments) {
   useApi(null);
   dart2js.main(arguments);
   elements.Name.isPublicName(null);
   useConstant();
   useNode(null);
@@ skipping 269 matching lines @@
 }
 
 useTreeVisitors() {
   new TreeVisitor1().visitExpression(null, null);
   new TreeVisitor1().visitStatement(null, null);
 }
 
 useDeferred([deferred.DeferredLoadTask task]) {
   task.dump();
 }