Add SdkPatcher and implement top-level function / getter / setter patching.

pkg/analyzer/lib/src/dart/sdk/sdk.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 analyzer.src.generated.sdk2;
 
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io' as io;
 
@@ skipping 48 matching lines @@
   InternalAnalysisContext _analysisContext;
 
   /**
    * The mapping from Dart URI's to the corresponding sources.
    */
   Map<String, Source> _uriToSourceMap = new HashMap<String, Source>();
 
   PackageBundle _sdkBundle;
 
   /**
+   * Return the analysis options for this SDK analysis context.
+   */
+  AnalysisOptions get analysisOptions => _analysisOptions;
+
+  /**
    * Set the [options] for this SDK analysis context.  Throw [StateError] if the
    * context has been already created.
    */
   void set analysisOptions(AnalysisOptions options) {
     if (_analysisContext != null) {
       throw new StateError(
           'Analysis options cannot be changed after context creation.');
     }
     _analysisOptions = options;
   }
@@ skipping 799 matching lines @@
     SdkLibrariesReader_LibraryBuilder libraryBuilder =
         new SdkLibrariesReader_LibraryBuilder(_useDart2jsPaths);
     // If any syntactic errors were found then don't try to visit the AST
     // structure.
     if (!errorListener.errorReported) {
       unit.accept(libraryBuilder);
     }
     return libraryBuilder.librariesMap;
   }
 }