Remove mask parameter from TypeMask.locateSingleElement

pkg/compiler/lib/src/types/union_type_mask.dart

Index: pkg/compiler/lib/src/types/union_type_mask.dart
diff --git a/pkg/compiler/lib/src/types/union_type_mask.dart b/pkg/compiler/lib/src/types/union_type_mask.dart
index 0f96e10c4f1814aed5874c441152032fd06010ae..32e4e2a457c1db634eb575a8e68a70f937219ab7 100644
--- a/pkg/compiler/lib/src/types/union_type_mask.dart
+++ b/pkg/compiler/lib/src/types/union_type_mask.dart
@@ -331,11 +331,10 @@ class UnionTypeMask implements TypeMask {
     return disjointMasks.any((e) => e.canHit(element, selector, classWorld));
   }
 
-  Element locateSingleElement(
-      Selector selector, TypeMask mask, Compiler compiler) {
+  Element locateSingleElement(Selector selector, Compiler compiler) {
     Element candidate;
     for (FlatTypeMask mask in disjointMasks) {
-      Element current = mask.locateSingleElement(selector, mask, compiler);

[sra1, 2016/08/26 00:45:27]

Was the argument supposed to be the parameter or the loop variable?

+      Element current = mask.locateSingleElement(selector, compiler);
       if (current == null) {
         return null;
       } else if (candidate == null) {