Support new import syntax.

tests/compiler/dart2js/dart_backend_test.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.
 
 #import('dart:uri');
 #import('parser_helper.dart');
 #import('mock_compiler.dart');
 #import("../../../lib/compiler/compiler.dart");
 #import("../../../lib/compiler/implementation/leg.dart", prefix:'leg');
 #import("../../../lib/compiler/implementation/dart_backend/dart_backend.dart");
@@ skipping 619 matching lines @@
 }
 
 testStaticAccessIoLib() {
   var src = '''
 #import('dart:io');
 
 main() {
   Platform.operatingSystem;
 }
 ''';
-  var expectedResult = '#import("dart:io",prefix:"p");'
+  var expectedResult = 'import "dart:io" as p;'
       'main(){p.Platform.operatingSystem;}';
   testDart2Dart(src,
       (String result) { Expect.equals(expectedResult, result); });
 }
 
 testMinification() {
   var src = '''
 class ClassWithVeryVeryLongName {}
 main() {
   new ClassWithVeryVeryLongName();
@@ skipping 109 matching lines @@
 #import('dart:html');
 
 class A {
   static String get userAgent => window.navigator.userAgent;
 }
 
 main() {
   A.userAgent;
 }
 ''';
-  var expectedResult = '#import("dart:html",prefix:"p");'
+  var expectedResult = 'import "dart:html" as p;'
       'class A{static String get userAgent=>p.window.navigator.userAgent;}'
       'main(){A.userAgent;}';
   testDart2Dart(src,
       (String result) { Expect.equals(expectedResult, result); });
 }
 
 main() {
   testSimpleFileUnparse();
   testTopLevelField();
   testSimpleTopLevelClass();
@@ skipping 20 matching lines @@
   testInterfaceDefaultAnotherLib();
   testStaticAccessIoLib();
   testLocalFunctionPlaceholder();
   testMinification();
   testClosureLocalsMinified();
   testParametersMinified();
   testTypeVariablesInDifferentLibraries();
   testDeclarationTypePlaceholders();
   testPlatformLibraryMemberNamesAreFixed();
 }