Finish strong mode cleaning of dart2js.

pkg/compiler/lib/src/ssa/locals_handler.dart

Index: pkg/compiler/lib/src/ssa/locals_handler.dart
diff --git a/pkg/compiler/lib/src/ssa/locals_handler.dart b/pkg/compiler/lib/src/ssa/locals_handler.dart
index d1c433b499243b95238e6e85dc6216e7e45a7a46..dd6ce4f634da3f33307ec3d24ccc32aea3a26488 100644
--- a/pkg/compiler/lib/src/ssa/locals_handler.dart
+++ b/pkg/compiler/lib/src/ssa/locals_handler.dart
@@ -154,8 +154,9 @@ class LocalsHandler {
     directLocals[closureInfo.context] = box;
     // Make sure that accesses to the boxed locals go into the box. We also
     // need to make sure that parameters are copied into the box if necessary.
-    closureInfo.forEachCapturedVariable(
-        (LocalVariableElement from, BoxFieldElement to) {
+    closureInfo.forEachCapturedVariable((_from, _to) {
+      LocalVariableElement from = _from;
+      BoxFieldElement to = _to;
       // The [from] can only be a parameter for function-scopes and not
       // loop scopes.
       if (from.isRegularParameter && !forGenerativeConstructorBody) {