Limit Mojo messages recursion depth

mojo/public/cpp/bindings/tests/validation_unittest.cc

Index: mojo/public/cpp/bindings/tests/validation_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/validation_unittest.cc b/mojo/public/cpp/bindings/tests/validation_unittest.cc
index 7b7dcbeee2fe835194379387a7784bfb02dfa185..1d3185dd6a93908eef26ff05716129ba283cab46 100644
--- a/mojo/public/cpp/bindings/tests/validation_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/validation_unittest.cc
@@ -424,6 +424,18 @@ TEST_F(ValidationTest, ResponseBoundsCheck) {
   RunValidationTests("resp_boundscheck_", &validators);
 }
 
+// Test that the client cannot send a message (e.g. a recursively defined
+// struct) so deep that the validation code blows the stack. The validation code
+// should check for this case and return a validation error.
+TEST_F(ValidationTest, RequestMaxRecursionDepth) {
+  DummyMessageReceiver dummy_receiver;
+  mojo::FilterChain validators(&dummy_receiver);
+  validators.Append<mojo::MessageHeaderValidator>();
+  validators.Append<RecursionDepthTestInterface::RequestValidator_>();
+
+  RunValidationTests("req_max_recursion_depth", &validators);
+}
+
 // Test that InterfacePtr<X> applies the correct validators and they don't
 // conflict with each other:
 //   - MessageHeaderValidator