Move a number of packages and some of pub over to using source_span.

pkg/yaml/lib/src/yaml_node_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 yaml.yaml_node_wrapper;
 
 import 'dart:collection';
 
 import 'package:collection/collection.dart' as pkg_collection;
-import 'package:source_maps/source_maps.dart';
+import 'package:source_span/source_span.dart';
 
 import 'null_span.dart';
 import 'yaml_node.dart';
 
 /// A wrapper that makes a normal Dart map behave like a [YamlMap].
 class YamlMapWrapper extends MapBase
     with pkg_collection.UnmodifiableMapMixin
     implements YamlMap {
   final Map _dartMap;
 
-  final Span span;
+  final SourceSpan span;
 
   final Map<dynamic, YamlNode> nodes;
 
   Map get value => this;
 
   Iterable get keys => _dartMap.keys;
 
-  YamlMapWrapper(Map dartMap, String sourceName)
-      : this._(dartMap, new NullSpan(sourceName));
+  YamlMapWrapper(Map dartMap, sourceUrl)
+      : this._(dartMap, new NullSpan(sourceUrl));
 
-  YamlMapWrapper._(Map dartMap, Span span)
+  YamlMapWrapper._(Map dartMap, SourceSpan span)
       : _dartMap = dartMap,
         span = span,
         nodes = new _YamlMapNodes(dartMap, span);
 
   operator [](Object key) {
     var value = _dartMap[key];
     if (value is Map) return new YamlMapWrapper._(value, span);
     if (value is List) return new YamlListWrapper._(value, span);
     return value;
   }
 
   int get hashCode => _dartMap.hashCode;
 
   operator ==(Object other) =>
       other is YamlMapWrapper && other._dartMap == _dartMap;
 }
 
 /// The implementation of [YamlMapWrapper.nodes] as a wrapper around the Dart
 /// map.
 class _YamlMapNodes extends MapBase<dynamic, YamlNode>
     with pkg_collection.UnmodifiableMapMixin<dynamic, YamlNode> {
   final Map _dartMap;
 
-  final Span _span;
+  final SourceSpan _span;
 
   Iterable get keys =>
       _dartMap.keys.map((key) => new YamlScalar.internal(key, _span));
 
   _YamlMapNodes(this._dartMap, this._span);
 
   YamlNode operator [](Object key) {
     // Use "as" here because key being assigned to invalidates type propagation.
     if (key is YamlScalar) key = (key as YamlScalar).value;
     if (!_dartMap.containsKey(key)) return null;
     return _nodeForValue(_dartMap[key], _span);
   }
 
   int get hashCode => _dartMap.hashCode;
 
   operator ==(Object other) =>
       other is _YamlMapNodes && other._dartMap == _dartMap;
 }
 
 // TODO(nweiz): Use UnmodifiableListMixin when issue 18970 is fixed.
 /// A wrapper that makes a normal Dart list behave like a [YamlList].
 class YamlListWrapper extends ListBase implements YamlList {
   final List _dartList;
 
-  final Span span;
+  final SourceSpan span;
 
   final List<YamlNode> nodes;
 
   List get value => this;
 
   int get length => _dartList.length;
 
   set length(int index) {
     throw new UnsupportedError("Cannot modify an unmodifiable List.");
   }
 
-  YamlListWrapper(List dartList, String sourceName)
-      : this._(dartList, new NullSpan(sourceName));
+  YamlListWrapper(List dartList, sourceUrl)
+      : this._(dartList, new NullSpan(sourceUrl));
 
-  YamlListWrapper._(List dartList, Span span)
+  YamlListWrapper._(List dartList, SourceSpan span)
       : _dartList = dartList,
         span = span,
         nodes = new _YamlListNodes(dartList, span);
 
   operator [](int index) {
     var value = _dartList[index];
     if (value is Map) return new YamlMapWrapper._(value, span);
     if (value is List) return new YamlListWrapper._(value, span);
     return value;
   }
 
   operator []=(int index, value) {
     throw new UnsupportedError("Cannot modify an unmodifiable List.");
   }
 
   int get hashCode => _dartList.hashCode;
 
   operator ==(Object other) =>
       other is YamlListWrapper && other._dartList == _dartList;
 }
 
 // TODO(nweiz): Use UnmodifiableListMixin when issue 18970 is fixed.
 /// The implementation of [YamlListWrapper.nodes] as a wrapper around the Dart
 /// list.
 class _YamlListNodes extends ListBase<YamlNode> {
   final List _dartList;
 
-  final Span _span;
+  final SourceSpan _span;
 
   int get length => _dartList.length;
 
   set length(int index) {
     throw new UnsupportedError("Cannot modify an unmodifiable List.");
   }
 
   _YamlListNodes(this._dartList, this._span);
 
   YamlNode operator [](int index) => _nodeForValue(_dartList[index], _span);
 
   operator []=(int index, value) {
     throw new UnsupportedError("Cannot modify an unmodifiable List.");
   }
 
   int get hashCode => _dartList.hashCode;
 
   operator ==(Object other) =>
       other is _YamlListNodes && other._dartList == _dartList;
 }
 
-YamlNode _nodeForValue(value, Span span) {
+YamlNode _nodeForValue(value, SourceSpan span) {
   if (value is Map) return new YamlMapWrapper._(value, span);
   if (value is List) return new YamlListWrapper._(value, span);
   return new YamlScalar.internal(value, span);
 }