Plumb "enableSuperMixins" option through analysis server (implements DEP 34).

pkg/analysis_server/test/integration/analysis/error_test.dart

 // Copyright (c) 2014, 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 test.integration.analysis.error;
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 17 matching lines @@
   print(null) // parse error: missing ';'
 }''');
     standardAnalysisSetup();
     return analysisFinished.then((_) {
       expect(currentAnalysisErrors[pathname], isList);
       List<AnalysisError> errors = currentAnalysisErrors[pathname];
       expect(errors, hasLength(1));
       expect(errors[0].location.file, equals(pathname));
     });
   }
+
+  test_super_mixins_disabled() async {
+    String pathname = sourcePath('test.dart');
+    writeFile(
+        pathname,
+        '''
+class Test extends Object with C {
+  void foo() {}
 }
+abstract class B {
+  void foo();
+}
+abstract class C extends B {
+  void bar() {
+    super.foo();
+  }
+}
+''');
+    standardAnalysisSetup();
+    await analysisFinished;
+    expect(currentAnalysisErrors[pathname], isList);
+    List<AnalysisError> errors = currentAnalysisErrors[pathname];
+    expect(errors, hasLength(2));
+    Set<String> allErrorMessages =
+        errors.map((AnalysisError e) => e.message).toSet();
+    expect(
+        allErrorMessages,
+        contains(
+            "The class 'C' cannot be used as a mixin because it extends a class other than Object"));
+    expect(
+        allErrorMessages,
+        contains(
+            "The class 'C' cannot be used as a mixin because it references 'super'"));
+  }
+
+  test_super_mixins_enabled() async {
+    String pathname = sourcePath('test.dart');
+    writeFile(
+        pathname,
+        '''
+class Test extends Object with C {
+  void foo() {}
+}
+abstract class B {
+  void foo();
+}
+abstract class C extends B {
+  void bar() {
+    super.foo();
+  }
+}
+''');
+    await sendAnalysisUpdateOptions(
+        new AnalysisOptions()..enableSuperMixins = true);
+    standardAnalysisSetup();
+    await analysisFinished;
+    expect(currentAnalysisErrors[pathname], isList);
+    List<AnalysisError> errors = currentAnalysisErrors[pathname];
+    expect(errors, isEmpty);
+  }
+}