Use ChannelMojo from the browser to NaCl loader process.

components/nacl/loader/BUILD.gn

Index: components/nacl/loader/BUILD.gn
diff --git a/components/nacl/loader/BUILD.gn b/components/nacl/loader/BUILD.gn
index b568a6b6bff6e54fa88e44dc2c5e6f04d079f685..cef8842020d8c8c48b5cae9b8b9e163318f0b60e 100644
--- a/components/nacl/loader/BUILD.gn
+++ b/components/nacl/loader/BUILD.gn
@@ -49,8 +49,10 @@ source_set("minimal_content_dummy") {
   check_includes = false
   sources = [
     "//content/public/common/child_process_sandbox_support_linux.h",
+    "//content/public/common/content_descriptors.h",
     "//content/public/common/content_switches.h",
     "//content/public/common/main_function_params.h",
+    "//content/public/common/mojo_channel_switches.h",
     "//content/public/common/sandbox_init.h",
   ]
 }
@@ -177,6 +179,7 @@ if (is_win && target_cpu == "x86" && current_cpu == "x64") {
       "//components/nacl/broker",
       "//components/nacl/common:switches",
       "//content/public/common:static_switches",
+      "//mojo/edk/system",
       "//sandbox",
     ]
   }