Fix for resynthesis when a part URI is empty.

pkg/analyzer/lib/src/summary/link.dart

 // Copyright (c) 2016, 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.
 
 /**
  * This library is capable of producing linked summaries from unlinked
  * ones (or prelinked ones).  It functions by building a miniature
  * element model to represent the contents of the summaries, and then
  * scanning the element model to gather linked information and adding
  * it to the summary data structures.
@@ skipping 3502 matching lines @@
 
   @override
   List<UnitElement> get units {
     if (_units == null) {
       UnlinkedUnit definingUnit = definingUnlinkedUnit;
       _units = <UnitElement>[
         _makeUnitElement(definingUnit, 0, _absoluteUri.toString())
       ];
       int numParts = definingUnit.parts.length;
       for (int i = 0; i < numParts; i++) {
-        // TODO(paulberry): make sure we handle the case where
-        // resolveRelativeUri fails.
         String partRelativeUriStr = definingUnit.publicNamespace.parts[i];
 
+        if (partRelativeUriStr.isEmpty) {
+          continue;
+        }
+
         Uri partRelativeUri;
         try {
           partRelativeUri = Uri.parse(partRelativeUriStr);
         } on FormatException {
           continue;
         }
 
         String partAbsoluteUri =
             resolveRelativeUri(_absoluteUri, partRelativeUri).toString();
         UnlinkedUnit partUnit = _linker.getUnit(partAbsoluteUri);
@@ skipping 1757 matching lines @@
 }
 
 /**
  * This exception is thrown when [ExprTypeComputer] cannot inference the type.
  */
 class _InferenceFailedError {
   final String message;
 
   _InferenceFailedError(this.message);
 }