Dart SDK Spelling b, c, and d.

pkg/front_end/testcases/DeltaBlue.dart

Index: pkg/front_end/testcases/DeltaBlue.dart
diff --git a/pkg/front_end/testcases/DeltaBlue.dart b/pkg/front_end/testcases/DeltaBlue.dart
index 755b8c3cc3a487826d37a040d50e74c29bca7a5a..d8eee80da20bd8f7b1af1d11b5373f0edf1fca3e 100644
--- a/pkg/front_end/testcases/DeltaBlue.dart
+++ b/pkg/front_end/testcases/DeltaBlue.dart
@@ -148,7 +148,7 @@ abstract class Constraint {
   /**
    * Normal constraints are not input constraints.  An input constraint
    * is one that depends on external state, such as the mouse, the
-   * keybord, a clock, or some arbitraty piece of imperative code.
+   * keybord, a clock, or some arbitrary piece of imperative code.
    */
   bool isInput() => false;
 }