Fix bug http://code.google.com/p/dart/issues/detail?id=12941 by doing speculative optimizations eve…

sdk/lib/_internal/compiler/implementation/types/type_mask.dart

Index: sdk/lib/_internal/compiler/implementation/types/type_mask.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/types/type_mask.dart	(revision 27115)
+++ sdk/lib/_internal/compiler/implementation/types/type_mask.dart	(working copy)
@@ -97,10 +97,9 @@
   TypeMask intersection(TypeMask other, Compiler compiler);
 
   /**
-   * Returns whether a [selector] call will hit a method at runtime,
-   * and not go through [noSuchMethod].
+   * Returns whether this [TypeMask] understands [selector].
    */
-  bool willHit(Selector selector, Compiler compiler);
+  bool understands(Selector selector, Compiler compiler);
 
   /**
    * Returns whether this [TypeMask] applied to [selector] can hit a