Add a flag to the element model to identify mixin applications.

pkg/analyzer/test/generated/all_the_rest_test.dart

Index: pkg/analyzer/test/generated/all_the_rest_test.dart
diff --git a/pkg/analyzer/test/generated/all_the_rest_test.dart b/pkg/analyzer/test/generated/all_the_rest_test.dart
index a45e0121e83a7b40eb6b12a57e4a5614320b3502..ddf26be6258f79cebdb1c3da02dbe77c8134f8bc 100644
--- a/pkg/analyzer/test/generated/all_the_rest_test.dart
+++ b/pkg/analyzer/test/generated/all_the_rest_test.dart
@@ -4817,6 +4817,7 @@ class ElementBuilderTest extends EngineTestCase {
     List<TypeParameterElement> typeParameters = type.typeParameters;
     expect(typeParameters, hasLength(0));
     expect(type.isAbstract, isTrue);
+    expect(type.isMixinApplication, isFalse);
     expect(type.isSynthetic, isFalse);
   }
 
@@ -4835,6 +4836,7 @@ class ElementBuilderTest extends EngineTestCase {
     List<TypeParameterElement> typeParameters = type.typeParameters;
     expect(typeParameters, hasLength(0));
     expect(type.isAbstract, isFalse);
+    expect(type.isMixinApplication, isFalse);
     expect(type.isSynthetic, isFalse);
   }
 
@@ -4859,6 +4861,7 @@ class ElementBuilderTest extends EngineTestCase {
     expect(typeParameters[0].name, firstVariableName);
     expect(typeParameters[1].name, secondVariableName);
     expect(type.isAbstract, isFalse);
+    expect(type.isMixinApplication, isFalse);
     expect(type.isSynthetic, isFalse);
   }
 
@@ -4885,6 +4888,7 @@ class ElementBuilderTest extends EngineTestCase {
     expect(type, isNotNull);
     expect(type.name, className);
     expect(type.isAbstract, isFalse);
+    expect(type.isMixinApplication, isFalse);
     expect(type.isSynthetic, isFalse);
     List<TypeParameterElement> typeParameters = type.typeParameters;
     expect(typeParameters, hasLength(1));
@@ -4926,6 +4930,7 @@ class ElementBuilderTest extends EngineTestCase {
     expect(alias.element, same(type));
     expect(type.name, equals('C'));
     expect(type.isAbstract, isFalse);
+    expect(type.isMixinApplication, isTrue);
     expect(type.isSynthetic, isFalse);
     expect(type.typeParameters, isEmpty);
     expect(type.fields, isEmpty);
@@ -4953,6 +4958,7 @@ class ElementBuilderTest extends EngineTestCase {
     expect(types, hasLength(1));
     ClassElement type = types[0];
     expect(type.isAbstract, isTrue);
+    expect(type.isMixinApplication, isTrue);
   }
 
   void test_visitClassTypeAlias_typeParams() {