Add tests for summarizing / resynthesizing using only AST.

pkg/analyzer/lib/src/summary/summarize_ast.dart

 // Copyright (c) 2016, 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 serialization.summarize_ast;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
@@ skipping 503 matching lines @@
     UnlinkedExecutableBuilder b = new UnlinkedExecutableBuilder();
     String nameString = name;
     if (isGetter) {
       b.kind = UnlinkedExecutableKind.getter;
     } else if (isSetter) {
       b.kind = UnlinkedExecutableKind.setter;
       nameString = '$nameString=';
     } else {
       b.kind = UnlinkedExecutableKind.functionOrMethod;
     }
-    b.isAbstract = body is EmptyFunctionBody;
+    b.isExternal = isExternal;
+    b.isAbstract = !isExternal && body is EmptyFunctionBody;
     b.name = nameString;
     b.nameOffset = nameOffset;
     b.typeParameters =
         serializeTypeParameters(typeParameters, typeParameterScope);
     if (!isTopLevel) {
       b.isStatic = isDeclaredStatic;
     }
     b.returnType = serializeTypeName(returnType);
-    b.isExternal = isExternal;
     bool isSemanticallyStatic = isTopLevel || isDeclaredStatic;
     if (formalParameters != null) {
       b.parameters = formalParameters.parameters
           .map((FormalParameter p) => p.accept(this))
           .toList();
       if (!isSemanticallyStatic) {
         for (int i = 0; i < formalParameters.parameters.length; i++) {
           if (!b.parameters[i].isFunctionTyped &&
               b.parameters[i].type == null) {
             b.parameters[i].inferredTypeSlot = assignSlot();
@@ skipping 339 matching lines @@
         }
       }
     }
     if (node.constKeyword != null) {
       b.isConst = true;
       b.constCycleSlot = assignSlot();
     }
     b.isExternal = node.externalKeyword != null;
     b.documentationComment = serializeDocumentation(node.documentationComment);
     b.annotations = serializeAnnotations(node.metadata);
+    b.codeRange = serializeCodeRange(node);
     if (node.constKeyword != null) {
       Set<String> constructorParameterNames =
           node.parameters.parameters.map((p) => p.identifier.name).toSet();
       b.constantInitializers = node.initializers
           .map((ConstructorInitializer initializer) =>
               serializeConstructorInitializer(initializer, (Expression expr) {
                 return serializeConstExpr(expr, constructorParameterNames);
               }))
           .toList();
     }
     serializeFunctionBody(b, node.body);
     executables.add(b);
   }
 
   @override
   UnlinkedParamBuilder visitDefaultFormalParameter(
       DefaultFormalParameter node) {
     UnlinkedParamBuilder b = node.parameter.accept(this);
     if (node.defaultValue != null) {
       b.defaultValue = serializeConstExpr(node.defaultValue);
       b.defaultValueCode = node.defaultValue.toSource();
     }
     b.initializer = serializeInitializerFunction(node.defaultValue);
+    b.codeRange = serializeCodeRange(node);
     return b;
   }
 
   @override
   void visitEnumDeclaration(EnumDeclaration node) {
     UnlinkedEnumBuilder b = new UnlinkedEnumBuilder();
     b.name = node.name.name;
     b.nameOffset = node.name.offset;
     b.values = node.constants
         .map((EnumConstantDeclaration value) => new UnlinkedEnumValueBuilder(
@@ skipping 226 matching lines @@
 /**
  * A [_TypeParameterScope] is a [_Scope] which defines [_ScopedTypeParameter]s.
  */
 class _TypeParameterScope extends _Scope {
   /**
    * Get the number of [_ScopedTypeParameter]s defined in this
    * [_TypeParameterScope].
    */
   int get length => _definedNames.length;
 }