Update charted to 0.4.8 and roll

packages/quiver/lib/src/cache/map_cache.dart

Index: packages/quiver/lib/src/cache/map_cache.dart
diff --git a/packages/quiver/lib/src/cache/map_cache.dart b/packages/quiver/lib/src/cache/map_cache.dart
index 3544422e4ef2a773c9eb35fa994da619f0ef5ead..e2364785a4811bbdf3215238970b5a4ba295e867 100644
--- a/packages/quiver/lib/src/cache/map_cache.dart
+++ b/packages/quiver/lib/src/cache/map_cache.dart
@@ -14,21 +14,15 @@
 
 part of quiver.cache;
 
-/**
- * A [Cache] that's backed by a [Map].
- */
+/// A [Cache] that's backed by a [Map].
 class MapCache<K, V> implements Cache<K, V> {
   final Map<K, V> _map;
 
-  /**
-   * Creates a new [MapCache], optionally using [map] as the backing [Map].
-   */
+  /// Creates a new [MapCache], optionally using [map] as the backing [Map].
   MapCache({Map<K, V> map}) : _map = map != null ? map : new HashMap<K, V>();
 
-  /**
-   * Creates a new [MapCache], using [LruMap] as the backing [Map].
-   * Optionally specify [maximumSize].
-   */
+  /// Creates a new [MapCache], using [LruMap] as the backing [Map].
+  /// Optionally specify [maximumSize].
   factory MapCache.lru({int maximumSize}) {
     return new MapCache<K, V>(map: new LruMap(maximumSize: maximumSize));
   }
@@ -38,12 +32,12 @@ class MapCache<K, V> implements Cache<K, V> {
       var valOrFuture = ifAbsent(key);
       if (valOrFuture is Future) {
         return valOrFuture.then((v) {
-          _map[key] = v;
-          return v;
+          _map[key] = v as V;
+          return v as V;
         });
       } else {
-        _map[key] = valOrFuture;
-        return new Future.value(valOrFuture);
+        _map[key] = valOrFuture as V;
+        return new Future<V>.value(valOrFuture);
       }
     }
     return new Future.value(_map[key]);