Rust: Add encoder/decoder tests

mojo/rust/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("rules.gni")
 
 group("rust") {
   testonly = true
   deps = [
     ":rust_embedder",
@@ skipping 18 matching lines @@
   assert(rustdoc_tool != "")
 
   cargo_out_dir = "debug"
   if (!is_debug) {
     cargo_out_dir = "release"
   }
   manifest = "//mojo/public/rust/Cargo.toml"
   lib_name = "lib" + target_name + ".rlib"
   deps = [
     "//mojo:system_thunks",
+    "//mojo/public/interfaces/bindings/tests:validation_parser",
     "//mojo/rust:rust_embedder",
   ]
   script = "//mojo/rust/cargo.py"
   inputs = [
     manifest,
   ]
   inputs += rust_mojo_sources
   args = [
     rust_cargo_tool,
     "test",
@@ skipping 23 matching lines @@
   sources = [
     "//mojo/rust/c_embedder/c_embedder.cc",
     "//mojo/rust/c_embedder/c_embedder.h",
   ]
   deps = [
     "//mojo/edk/base_edk",
     "//mojo/edk/system",
     "//mojo/public/interfaces/bindings/tests:test_interfaces",
   ]
 }