Add some user-friendly utility functions to pkg/analyzer_experimental.

pkg/analyzer_experimental/lib/src/analyzer_impl.dart

Index: pkg/analyzer_experimental/lib/src/analyzer_impl.dart
diff --git a/pkg/analyzer_experimental/lib/analyzer.dart b/pkg/analyzer_experimental/lib/src/analyzer_impl.dart
similarity index 91%
copy from pkg/analyzer_experimental/lib/analyzer.dart
copy to pkg/analyzer_experimental/lib/src/analyzer_impl.dart
index 47f0129246e018a4386d3610ec63803b26f8344f..40b8deb3cba517f9dfd1c8ac4a883b4155922b0c 100644
--- a/pkg/analyzer_experimental/lib/analyzer.dart
+++ b/pkg/analyzer_experimental/lib/src/analyzer_impl.dart
@@ -1,10 +1,24 @@
 // Copyright (c) 2013, 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.
-part of analyzer;
+
+library analyzer_impl;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'generated/java_io.dart';
+import 'generated/engine.dart';
+import 'generated/error.dart';
+import 'generated/source_io.dart';
+import 'generated/sdk.dart';
+import 'generated/sdk_io.dart';
+import 'generated/ast.dart';
+import 'generated/element.dart';
+import '../options.dart';
 
 /// Analyzes single library [File].
-class _AnalyzerImpl {
+class AnalyzerImpl {
   final CommandLineOptions options;
   DartSdk sdk;
 
@@ -18,7 +32,7 @@ class _AnalyzerImpl {
   /// All [AnalysisErrorInfo]s in the analyzed library.
   final List<AnalysisErrorInfo> errorInfos = new List<AnalysisErrorInfo>();
 
-  _AnalyzerImpl(CommandLineOptions this.options) {
+  AnalyzerImpl(CommandLineOptions this.options) {
     sdk = new DirectoryBasedDartSdk(new JavaFile(options.dartSdkPath));
   }