Add an error callback to StackZoneSpecification.

pkg/stack_trace/lib/src/chain.dart

 // 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 stack_trace.chain;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'frame.dart';
@@ skipping 84 matching lines @@
         return callback();
       } catch (error, stackTrace) {
         // TODO(nweiz): Don't special-case this when issue 19566 is fixed.
         return Zone.current.handleUncaughtError(error, stackTrace);
       }
     }, zoneSpecification: spec.toSpec(), zoneValues: {
       #stack_trace.stack_zone.spec: spec
     });
   }
 
-  /// Ensures that any errors emitted by [futureOrStream] have the correct stack
-  /// chain information associated with them.
+  /// Returns [futureOrStream] unmodified.
   ///
-  /// For the most part an error thrown within a [capture] zone will have the
-  /// correct stack chain automatically associated with it. However, there are
-  /// some cases where exceptions won't be automatically detected: any [Future]
-  /// constructor, [Completer.completeError], [Stream.addError], and libraries
-  /// that use these.
-  ///
-  /// This returns a [Future] or [Stream] that will emit the same values and
-  /// errors as [futureOrStream]. The only exception is that if [futureOrStream]
-  /// emits an error without a stack trace, one will be added in the return
-  /// value.
-  ///
-  /// If this is called outside of a [capture] zone, it just returns
-  /// [futureOrStream] as-is.
-  ///
-  /// As the name suggests, [futureOrStream] may be either a [Future] or a
-  /// [Stream].
-  static track(futureOrStream) {
-    if (_currentSpec == null) return futureOrStream;
-    if (futureOrStream is Future) {
-      return _currentSpec.trackFuture(futureOrStream, 1);
-    } else {
-      return _currentSpec.trackStream(futureOrStream, 1);
-    }
-  }
+  /// Prior to Dart 1.7, this was necessary to ensure that stack traces for
+  /// exceptions reported with [Completer.completeError] and
+  /// [StreamController.addError] were tracked correctly.
+  @Deprecated("Chain.track is not necessary in Dart 1.7+.")
+  static track(futureOrStream) => futureOrStream;
 
   /// Returns the current stack chain.
   ///
   /// By default, the first frame of the first trace will be the line where
   /// [Chain.current] is called. If [level] is passed, the first trace will
   /// start that many frames up instead.
   ///
   /// If this is called outside of a [capture] zone, it just returns a
   /// single-trace chain.
   factory Chain.current([int level=0]) {
@@ skipping 72 matching lines @@
   }
 
   /// Converts [this] to a [Trace].
   ///
   /// The trace version of a chain is just the concatenation of all the traces
   /// in the chain.
   Trace toTrace() => new Trace(flatten(traces.map((trace) => trace.frames)));
 
   String toString() => traces.join(_GAP);
 }