Added support for GN workspaces.

pkg/analyzer/lib/src/context/builder.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.context.context_builder;
 
 import 'dart:collection';
 import 'dart:core';
 
 import 'package:analyzer/context/declared_variables.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/plugin/resolver_provider.dart';
 import 'package:analyzer/source/analysis_options_provider.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/command_line/arguments.dart'
     show applyAnalysisOptionFlags;
 import 'package:analyzer/src/dart/sdk/sdk.dart';
 import 'package:analyzer/src/generated/bazel.dart';
 import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/gn.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/summary/package_bundle_reader.dart';
 import 'package:analyzer/src/summary/pub_summary.dart';
 import 'package:analyzer/src/summary/summary_sdk.dart';
 import 'package:analyzer/src/task/options.dart';
 import 'package:args/args.dart';
 import 'package:package_config/packages.dart';
 import 'package:package_config/packages_file.dart';
 import 'package:package_config/src/packages_impl.dart';
@@ skipping 171 matching lines @@
         BazelWorkspace.find(resourceProvider, rootPath);
     if (bazelWorkspace != null) {
       List<UriResolver> resolvers = <UriResolver>[
         new DartUriResolver(findSdk(null, options)),
         new BazelPackageUriResolver(bazelWorkspace),
         new BazelFileUriResolver(bazelWorkspace)
       ];
       return new SourceFactory(resolvers, null, resourceProvider);
     }
 
+    GnWorkspace gnWorkspace = GnWorkspace.find(resourceProvider, rootPath);
+    if (gnWorkspace != null) {
+      DartSdk sdk = findSdk(gnWorkspace.packageMap, options);
+      List<UriResolver> resolvers = <UriResolver>[
+        new DartUriResolver(sdk),
+        new GnPackageUriResolver(gnWorkspace),
+        new GnFileUriResolver(gnWorkspace)
+      ];
+      return new SourceFactory(resolvers, null, resourceProvider);
+    }
+
     Packages packages = createPackageMap(rootPath);
     Map<String, List<Folder>> packageMap = convertPackagesToMap(packages);
     List<UriResolver> resolvers = <UriResolver>[
       new DartUriResolver(findSdk(packageMap, options)),
       new PackageMapUriResolver(resourceProvider, packageMap),
       new ResourceUriResolver(resourceProvider)
     ];
     return new SourceFactory(resolvers, packages, resourceProvider);
   }
 
@@ skipping 410 matching lines @@
   String _readEmbedderYaml(Folder libDir) {
     File file = libDir.getChild(EMBEDDER_FILE_NAME);
     try {
       return file.readAsStringSync();
     } on FileSystemException {
       // File can't be read.
       return null;
     }
   }
 }