Make mojom targets depend on chromium mojo environment

mojo/edk/js/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_edk.gni")
 import("../../../../third_party/mojo/src/mojo/public/tools/bindings/mojom.gni")
 
 mojo_edk_source_set("js_to_cpp_tests") {
   testonly = true
 
@@ skipping 10 matching lines @@
 
   sources = [
     "js_to_cpp_tests.cc",
   ]
 }
 
 mojom("js_to_cpp_bindings") {
   sources = [
     "js_to_cpp.mojom",
   ]
+
+  with_environment = false
 }