Use ChannelMojo from the browser to NaCl loader process.

patch from issue 2081183005 at patchset 340001 (http://crrev.com/2081183005#ps340001)

BUG=604282
[email protected]

Review-Url: https://codereview.chromium.org/2305913002
Cr-Commit-Position: refs/heads/master@{#420245}
diff --git a/content/BUILD.gn b/content/BUILD.gn
index d332c24..64033c01 100644
--- a/content/BUILD.gn
+++ b/content/BUILD.gn
@@ -89,6 +89,7 @@
       "common/sandbox_linux/sandbox_seccomp_bpf_linux.cc",
       "common/send_zygote_child_ping_linux.cc",
       "public/common/content_switches.cc",
+      "public/common/mojo_channel_switches.cc",
     ]
     set_sources_assignment_filter(sources_assignment_filter)