C bindings: Implement _Validate(), and some pre-requisites

mojo/public/cpp/bindings/tests/BUILD.gn

 # Copyright 2014 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("../../../mojo_application.gni")
 import("../../../mojo_sdk.gni")
 
 mojo_sdk_source_set("tests") {
   testonly = true
 
@@ skipping 30 matching lines @@
     "struct_unittest.cc",
     "synchronous_connector_unittest.cc",
     "synchronous_interface_ptr_unittest.cc",
     "type_conversion_unittest.cc",
     "union_unittest.cc",
     "validation_unittest.cc",
   ]
 
   deps = [
     ":mojo_public_bindings_test_utils",
+    ":validation_util",
     "//testing/gtest",
   ]
 
   mojo_sdk_deps = [
     "mojo/public/cpp/bindings",
     "mojo/public/cpp/bindings:callback",
     "mojo/public/cpp/environment:standalone",
     "mojo/public/cpp/system",
     "mojo/public/cpp/test_support",
     "mojo/public/cpp/test_support:test_utils",
@@ skipping 18 matching lines @@
     "mojo/public/cpp/bindings",
     "mojo/public/cpp/bindings:callback",
     "mojo/public/cpp/environment:standalone",
     "mojo/public/cpp/system",
     "mojo/public/cpp/test_support",
     "mojo/public/cpp/utility",
     "mojo/public/interfaces/bindings/tests:test_interfaces",
   ]
 }
 
+# TODO(vardhan): This should be testonly, but for that to happen, its
+# dependents (cython etc.) need also be testonly.
 mojo_sdk_source_set("mojo_public_bindings_test_utils") {
   sources = [
     "validation_test_input_parser.cc",
     "validation_test_input_parser.h",
   ]
 
   mojo_sdk_deps = [ "mojo/public/c/system" ]
 }
 
+# TODO(vardhan): Merge with mojo_public_bindings_test_utils. 
+mojo_sdk_source_set("validation_util") {
+  testonly = true
+
+  sources = [
+    "validation_util.cc",
+    "validation_util.h",
+  ]
+
+  mojo_sdk_deps = [
+    "mojo/public/c/system",
+    "mojo/public/cpp/test_support",
+  ]
+
+  deps = [
+    ":mojo_public_bindings_test_utils",
+    "//testing/gtest",
+  ]
+}
+
 mojo_native_application("versioning_test_service") {
   testonly = true
 
   deps = [
     ":versioning_test_service_source_set",
   ]
 }
 
 mojo_sdk_source_set("versioning_test_service_source_set") {
   testonly = true
@@ skipping 31 matching lines @@
   ]
 
   mojo_sdk_deps = [
     "mojo/public/cpp/application:standalone",
     "mojo/public/cpp/application:test_support_standalone",
     "mojo/public/cpp/bindings",
     "mojo/public/cpp/system",
     "mojo/public/interfaces/bindings/tests:versioning_test_client_interfaces",
   ]
 }