Adding isNotEmpty property to collection and string.

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index a0b627850ce552666a0edfab998b9d2ce7b310d6..705e24ce3aa12d8af5a36ba26d3cf923cbafe811 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -21245,6 +21245,8 @@ class Storage extends NativeFieldWrapperClass1 implements Map<String, String>
   int get length => $dom_length;
 
   bool get isEmpty => $dom_key(0) == null;
+
+  bool get isNotEmpty => !isEmpty;
   Storage.internal();
 
   @DomName('Storage.length')
@@ -26725,6 +26727,11 @@ abstract class _AttributeMap implements Map<String, String> {
   }
 
   /**
+   * Returns true if there is at least one {key, value} pair in the map.
+   */
+  bool get isNotEmpty => !isEmpty;
+
+  /**
    * Checks to see if the node should be included in this map.
    */
   bool _matches(Node node);
@@ -26871,6 +26878,8 @@ class _DataAttributeMap implements Map<String, String> {
   // TODO: Use lazy iterator when it is available on Map.
   bool get isEmpty => length == 0;
 
+  bool get isNotEmpty => !isEmpty;
+
   // Helpers.
   String _attr(String key) => 'data-$key';
   bool _matches(String key) => key.startsWith('data-');
@@ -31037,6 +31046,7 @@ class _DOMStringMap extends NativeFieldWrapperClass1 implements Map<String, Stri
   Iterable<String> get values => Maps.getValues(this);
   int get length => Maps.length(this);
   bool get isEmpty => Maps.isEmpty(this);
+  bool get isNotEmpty => Maps.isNotEmpty(this);
 }
 
 final Future<SendPort> __HELPER_ISOLATE_PORT =