Introduce code to generate summaries from an element model.

pkg/analyzer/test/generated/resolver_test.dart

Index: pkg/analyzer/test/generated/resolver_test.dart
diff --git a/pkg/analyzer/test/generated/resolver_test.dart b/pkg/analyzer/test/generated/resolver_test.dart
index b308c9be98101514d416075f194eb7abe0677467..98ae082bf0c0d83c3a7b8a0dfd4a9f9ce491e8ff 100644
--- a/pkg/analyzer/test/generated/resolver_test.dart
+++ b/pkg/analyzer/test/generated/resolver_test.dart
@@ -136,6 +136,7 @@ class AnalysisContextFactory {
     coreContext.setContents(coreSource, "");
     coreUnit.librarySource = coreUnit.source = coreSource;
     ClassElementImpl proxyClassElement = ElementFactory.classElement2("_Proxy");
+    proxyClassElement.constructors = <ConstructorElement>[];
     ClassElement objectClassElement = provider.objectType.element;
     coreUnit.types = <ClassElement>[
       provider.boolType.element,
@@ -258,8 +259,8 @@ class AnalysisContextFactory {
         streamElement.type.typeArguments;
     (parameterTypes[0] as FunctionTypeImpl).typeArguments =
         streamElement.type.typeArguments;
-    (parameterTypes[0].element as FunctionElementImpl)
-        .enclosingElement = listenMethod;
+    (parameterTypes[0].element as FunctionElementImpl).enclosingElement =
+        listenMethod;
     streamElement.methods = <MethodElement>[listenMethod];
 
     asyncUnit.types = <ClassElement>[