Reapply "Added for-loop variable tracking and regular closures/initializers captured variable track…

pkg/compiler/lib/src/kernel/element_map_impl.dart

Index: pkg/compiler/lib/src/kernel/element_map_impl.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map_impl.dart b/pkg/compiler/lib/src/kernel/element_map_impl.dart
index 4853ab03814be4cb847b24cfb9f85f67bc25a652..6182f1bd43d6479f82e06b38a0e9028b5e06de40 100644
--- a/pkg/compiler/lib/src/kernel/element_map_impl.dart
+++ b/pkg/compiler/lib/src/kernel/element_map_impl.dart
@@ -1782,7 +1782,10 @@ class JsKernelToElementMap extends KernelToElementMapBase
 
   @override
   Local _getLocalFunction(ir.TreeNode node) {
-    throw new UnsupportedError("JsKernelToElementMap.getLocalFunction");
+    // TODO(efortuna, johnniwinther): This function should not be called once
+    // the K + J element situation has been properly sorted out. Ultimately this
+    // should throw.
+    return _elementMap.getLocalFunction(node);
   }
 
   @override