Use Mojo pipes to signal sync IPC events

components/nacl/loader/BUILD.gn

 # Copyright 2015 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("//build/config/features.gni")
 import("//build/config/nacl/config.gni")
 import("//testing/test.gni")
 
 assert(enable_nacl)
 
@@ skipping 15 matching lines @@
     "nacl_validation_query.cc",
     "nacl_validation_query.h",
   ]
 
   deps = [
     ":minimal_content_dummy",
     "//base",
     "//components/nacl/common:minimal",
     "//crypto",
     "//ipc",
+    "//mojo/edk/system",
     "//native_client/src/trusted/service_runtime:sel_main_chrome",
     "//ppapi/c",
     "//ppapi/proxy:ipc",
     "//sandbox",
   ]
 }
 
 # This exists just to make 'gn check' happy with :minimal and
 # :nacl_helper_win_64 (below).  They can't depend on //content/public/common
 # or anything like that, because that would bring in lots more than counts
@@ skipping 229 matching lines @@
       "${root_out_dir}/nacl_helper_nonsfi_unittests_main",
     ]
     outputs = [
       "${root_build_dir}/{{source_file_part}}",
     ]
     deps = [
       ":nacl_helper_nonsfi_unittests_main",
     ]
   }
 }