Support source_span spans in barback.

pkg/barback/lib/src/span_wrapper.dart

 // Copyright (c) 2014, 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 source_maps.span_wrapper;
 
+import 'package:source_maps/source_maps.dart';
 import 'package:source_span/source_span.dart' as source_span;
 
-import '../span.dart';
-
 /// A wrapper that exposes a [source_span.SourceSpan] as a [Span].
 class SpanWrapper extends Span {
   final source_span.SourceSpan _inner;
 
   String get text => _inner.text;
 
   SpanWrapper(source_span.SourceSpan inner, bool isIdentifier)
       : _inner = inner,
         super(
             new LocationWrapper(inner.start),
@@ skipping 16 matching lines @@
 
   LocationWrapper(source_span.SourceLocation inner)
       : _inner = inner,
         super(inner.offset);
 
   static Location wrap(location) {
     if (location is Location) return location;
     return new LocationWrapper(location);
   }
 }
-
-/// A wrapper that exposes a [source_span.SourceFile] as a [SourceFile].
-class SourceFileWrapper implements SourceFile {
-  final source_span.SourceFile _inner;
-
-  // These are necessary to avoid analyzer warnings;
-  final _lineStarts = null;
-  final _decodedChars = null;
-
-  String get url => _inner.url.toString();
-
-  SourceFileWrapper(this._inner);
-
-  static SourceFile wrap(sourceFile) {
-    if (sourceFile is SourceFile) return sourceFile;
-    return new SourceFileWrapper(sourceFile);
-  }
-
-  Span span(int start, [int end, bool isIdentifier = false]) {
-    if (end == null) end = start;
-    return new SpanWrapper(_inner.span(start, end), isIdentifier);
-  }
-
-  Location location(int offset) => new LocationWrapper(_inner.location(offset));
-
-  int getLine(int offset) => _inner.getLine(offset);
-
-  int getColumn(int line, int offset) => _inner.getColumn(offset, line: line);
-
-  int getOffset(int line, int column) => _inner.getOffset(line, column);
-
-  String getText(int start, [int end]) => _inner.getText(start, end);
-
-  String getLocationMessage(String message, int start, int end,
-      {bool useColors: false, String color}) {
-    return span(start, end).getLocationMessage(message,
-        useColors: useColors, color: color);
-  }
-}