Move implementation from IterableBase to Iterable.

sdk/lib/_internal/compiler/js_lib/js_helper.dart

Index: sdk/lib/_internal/compiler/js_lib/js_helper.dart
diff --git a/sdk/lib/_internal/compiler/js_lib/js_helper.dart b/sdk/lib/_internal/compiler/js_lib/js_helper.dart
index c2d26ff6029d370bb550d704d0e1ea60ccc402a2..bb22a2fdce13d5954ddecb7bc395941c2aa2fca4 100644
--- a/sdk/lib/_internal/compiler/js_lib/js_helper.dart
+++ b/sdk/lib/_internal/compiler/js_lib/js_helper.dart
@@ -3972,7 +3972,7 @@ class SyncStarIterator implements Iterator {
 /// An Iterable corresponding to a sync* method.
 ///
 /// Each invocation of a sync* method will return a new instance of this class.
-class SyncStarIterable extends IterableBase {
+class SyncStarIterable extends Iterable {
   // This is a function that will return a helper function that does the
   // iteration of the sync*.
   //