use List.unmodifiable when possible

[email protected]

Review URL: https://codereview.chromium.org//1940453003 .

Author: kevmoo

lib/src/chain.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:collection';
 import 'dart:math' as math;
 
 import 'frame.dart';
@@ -146,7 +145,7 @@ class Chain implements StackTrace {
 
   /// Returns a new [Chain] comprised of [traces].
   Chain(Iterable<Trace> traces)
-      : traces = new UnmodifiableListView<Trace>(traces.toList());
+      : traces = new List<Trace>.unmodifiable(traces);
 
   /// Returns a terser version of [this].
   ///

lib/src/trace.dart

@@ -2,7 +2,6 @@
 // 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.
 
-import 'dart:collection';
 import 'dart:math' as math;
 
 import 'chain.dart';
@@ -205,7 +204,7 @@ class Trace implements StackTrace {
 
   /// Returns a new [Trace] comprised of [frames].
   Trace(Iterable<Frame> frames)
-      : frames = new UnmodifiableListView<Frame>(frames.toList());
+      : frames = new List<Frame>.unmodifiable(frames);
 
   /// Returns a VM-style [StackTrace] object.
   ///

pubspec.yaml

@@ -7,9 +7,9 @@ name: stack_trace
 #
 # When the major version is upgraded, you *must* update that version constraint
 # in pub to stay in sync with this.
-version: 1.6.5
+version: 1.6.6-dev
 author: "Dart Team <[email protected]>"
-homepage: http://github.com/dart-lang/stack_trace
+homepage: https://github.com/dart-lang/stack_trace
 description: >
   A package for manipulating stack traces and printing them readably.