Updated charted DEP to 0.4.X

packages/charted/lib/core/text_metrics/segmentation.dart

 //
 // Copyright 2014 Google Inc. All rights reserved.
 //
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 //
 
 library charted.core.text_metrics.segmentation;
 
@@ skipping 167 matching lines @@
     }
     if (CODE_POINT_BLOCKS[idx] > rune) {
       max = mid - 1;
     } else if (CODE_POINT_BLOCKS[idx + 1] < rune) {
       min = max + 1;
     }
   }
   return CODE_CATEGORY_OTHER; // Defaults to OTHER.
 }
 
-Iterable<int> graphemeBreakIndices(String s) {
+List<int> graphemeBreakIndices(String s) {
   List<int> indices = [];
   int previousType = 0;
   for (var iter = s.runes.iterator; iter.moveNext();) {
     int currentType = _typeForRune(iter.current);
     if (GRAPHEME_BREAK_TABLE[previousType * 12 + currentType] == 1) {
       indices.add(iter.rawIndex);
     }
     previousType = currentType;
   }
   return indices;
 }