Fix source information positions for deserialized patched elements.

pkg/compiler/lib/src/elements/elements.dart

Index: pkg/compiler/lib/src/elements/elements.dart
diff --git a/pkg/compiler/lib/src/elements/elements.dart b/pkg/compiler/lib/src/elements/elements.dart
index 0216f562bad7ca5d9890368b7f1163ed73076d8d..ad854f514e0ee5b05d09aa013487b3c144c4671a 100644
--- a/pkg/compiler/lib/src/elements/elements.dart
+++ b/pkg/compiler/lib/src/elements/elements.dart
@@ -1686,6 +1686,10 @@ abstract class ResolvedAst {
   /// The [TreeElements] containing the resolution data for [node]. This only
   /// available of [kind] is `ResolvedAstKind.PARSED`.
   TreeElements get elements;
+
+  /// Returns the uri for the source file defining [node] and [body]. This
+  /// only available if [kind] is `ResolvedAstKind.PARSED`.
+  Uri get sourceUri;
 }
 
 /// [ResolvedAst] implementation used for elements whose semantics is defined in
@@ -1695,8 +1699,10 @@ class ParsedResolvedAst implements ResolvedAst {
   final Node node;
   final Node body;
   final TreeElements elements;
+  final Uri sourceUri;
 
-  ParsedResolvedAst(this.element, this.node, this.body, this.elements);
+  ParsedResolvedAst(
+      this.element, this.node, this.body, this.elements, this.sourceUri);
 
   ResolvedAstKind get kind => ResolvedAstKind.PARSED;
 
@@ -1726,6 +1732,11 @@ class SynthesizedResolvedAst implements ResolvedAst {
     throw new UnsupportedError('$this does not have a body AST node');
   }
 
+  @override
+  Uri get sourceUri {
+    throw new UnsupportedError('$this does not have a source URI');
+  }
+
   String toString() => '$kind:$element';
 }