Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/analyzer/src/string_source.dart

Index: observatory_pub_packages/analyzer/src/string_source.dart
===================================================================
--- observatory_pub_packages/analyzer/src/string_source.dart	(revision 0)
+++ observatory_pub_packages/analyzer/src/string_source.dart	(working copy)
@@ -0,0 +1,49 @@
+// 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.
+
+library analyzer.string_source;
+
+import 'generated/source.dart';
+import 'generated/engine.dart' show TimestampedData;
+
+/// An implementation of [Source] that's based on an in-memory Dart string.
+class StringSource implements Source {
+  final String _contents;
+  final String fullName;
+  final int modificationStamp;
+
+  StringSource(this._contents, this.fullName)
+      : modificationStamp = new DateTime.now().millisecondsSinceEpoch;
+
+  bool operator==(Object object) {
+    if (object is StringSource) {
+      StringSource ssObject = object;
+      return ssObject._contents == _contents && ssObject.fullName == fullName;
+    }
+    return false;
+  }
+
+  bool exists() => true;
+
+  TimestampedData<String> get contents => new TimestampedData(modificationStamp, _contents);
+
+  String get encoding => throw new UnsupportedError("StringSource doesn't support "
+      "encoding.");
+
+  String get shortName => fullName;
+
+  UriKind get uriKind => throw new UnsupportedError("StringSource doesn't support "
+      "uriKind.");
+
+  int get hashCode => _contents.hashCode ^ fullName.hashCode;
+
+  bool get isInSystemLibrary => false;
+
+  @override
+  Uri get uri => throw new UnsupportedError(
+      "StringSource doesn't support uri.");
+
+  Uri resolveRelativeUri(Uri relativeUri) => throw new UnsupportedError(
+      "StringSource doesn't support resolveRelative.");
+}