Information for the migration result pages

Change-Id: I237efbbd1ed50963b28dce738c2a365c244b3a88
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/117587
Reviewed-by: Samuel Rawlins <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>

Author: bwilkerson

pkg/analysis_server/lib/src/edit/nnbd_migration/migration_info.dart

@@ -0,0 +1,45 @@
+// Copyright (c) 2019, 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.
+
+/// The migration information associated with a single library.
+class LibraryInfo {
+  /// The information about the units in the library. The information about the
+  /// defining compilation unit is always first.
+  final List<UnitInfo> units;
+
+  /// Initialize a newly created library.
+  LibraryInfo(this.units);
+}
+
+/// A description of an explanation associated with a region of code that was
+/// modified.
+class RegionInfo {
+  /// The offset to the beginning of the region.
+  final int offset;
+
+  /// The length of the region.
+  final int length;
+
+  /// The explanation to be displayed for the region.
+  final String explanation;
+
+  /// Initialize a newly created region.
+  RegionInfo(this.offset, this.length, this.explanation);
+}
+
+/// The migration information associated with a single compilation unit.
+class UnitInfo {
+  /// The absolute and normalized path of the unit.
+  final String path;
+
+  /// The content of unit.
+  final String content;
+
+  /// The information about the regions that have an explanation associated with
+  /// them.
+  final List<RegionInfo> regions;
+
+  /// Initialize a newly created unit.
+  UnitInfo(this.path, this.content, this.regions);
+}