Launch nexes from mojo_shell.

mojo/nacl/BUILD.gn

 # All toolchains use the same generated code.
 gen_dir = "$root_build_dir/gen/mojo/nacl"
 
 # Only allow the generator to be run by one toolchain.
 if (current_toolchain == default_toolchain) {
   # Generate the code to plumb the Mojo public API into the NaCl sandbox.
   action("mojo_nacl_codegen") {
     script = "generator/generate_nacl_bindings.py"
     args = [
       "-d",
@@ skipping 48 matching lines @@
 }
 
 # Untrusted code
 if (is_nacl) {
   # Thunk mapping the Mojo public API onto NaCl syscalls.
   static_library("mojo") {
     sources = [
       "$gen_dir/libmojo.cc",
     ]
     deps = [
+      "//native_client/src/untrusted/nacl:imc_syscalls",
       ":mojo_nacl_codegen($default_toolchain)",
     ]
   }
 
   # Unit test for the Mojo public API.
   executable("monacl_test") {
     testonly = true
     sources = [
       "//mojo/public/cpp/system/tests/core_unittest.cc",
       "//mojo/public/cpp/system/tests/macros_unittest.cc",
     ]
     deps = [
-      "//native_client/src/untrusted/nacl:imc_syscalls",
       "//mojo/public/c/system/tests:tests",
       "//mojo/public/cpp/system:system",
       "//testing/gtest:gtest",
       "//testing/gtest:gtest_main",
       ":mojo",
     ]
   }
 
   executable("irt_mojo") {
     cflags_c = [ "-std=c99" ]
@@ skipping 14 matching lines @@
   ]
 }
 
 group("mojo_nacl_tests") {
   testonly = true
   deps = [
     ":monacl_shell",
     ":monacl_test(//native_client/build/toolchain/nacl:clang_newlib_${cpu_arch})",
   ]
 }