Adds method ordinal off-by-one error detection testing to ValidationTest.

mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom

Index: mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom
diff --git a/mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom b/mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom
index cd5e1aa6538569b65e63efe688010fa509aa8031..37b7f47e79747082b9142dbe1f903cec2bbbbda0 100644
--- a/mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom
+++ b/mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom
@@ -41,6 +41,15 @@ struct StructG {
   bool b;
 };
 
+// This interface is used for testing bounds-checking in the mojom
+// binding code. If you add a method please update the files
+// ./data/validation/boundscheck_*. If you add a response please update
+// ./data/validation/resp_boundscheck_*.
+interface BoundsCheckTestInterface {
+  Method0(uint8 param0) => (uint8 param0);
+  Method1(uint8 param0);
+};
+
 interface ConformanceTestInterface {
   Method0(float param0);
   Method1(StructA param0);