Add validation logic for non-nullable types.

mojo/public/interfaces/bindings/tests/data/validation/conformance_mthd9_good.data

Index: mojo/public/interfaces/bindings/tests/data/validation/conformance_mthd9_good.data
diff --git a/mojo/public/interfaces/bindings/tests/data/validation/conformance_mthd9_good.data b/mojo/public/interfaces/bindings/tests/data/validation/conformance_mthd9_good.data
new file mode 100644
index 0000000000000000000000000000000000000000..c548906f0bef6dedfc3732aaef265ef13963e0f1
--- /dev/null
+++ b/mojo/public/interfaces/bindings/tests/data/validation/conformance_mthd9_good.data
@@ -0,0 +1,34 @@
+[handles]4
+
+[dist4]message_header  // num_bytes
+[u4]2                  // num_fields
+[u4]9                  // name
+[u4]0                  // flags
+[anchr]message_header
+
+[dist4]method9_params  // num_bytes
+[u4]1                  // num_fields
+[dist8]param0_ptr      // param0
+[anchr]method9_params
+
+[anchr]param0_ptr
+[dist4]array_param         // num_bytes
+[u4]2                      // num_elements
+[dist8]nested_array_ptr_0
+[dist8]nested_array_ptr_1
+[anchr]array_param
+
+[anchr]nested_array_ptr_0
+[dist4]nested_array_0  // num_bytes
+[u4]2                  // num_elements
+[u4]0
+[s4]-1                 // An invalid handle, which is okay.
+[anchr]nested_array_0
+
+[anchr]nested_array_ptr_1
+[dist4]nested_array_1  // num_bytes
+[u4]3                  // num_elements
+[u4]2
+[s4]-1                 // An invalid handle, which is okay.
+[u4]3
+[anchr]nested_array_1