Land prep work to enable NaCl in the Linux x64 GN builds.

chrome/BUILD.gn

Index: chrome/BUILD.gn
diff --git a/chrome/BUILD.gn b/chrome/BUILD.gn
index ab95acd332d77b7c978bb308a9f7e4d8fade02a3..560c0025bfe506816474a507a2598ef391c2cf64 100644
--- a/chrome/BUILD.gn
+++ b/chrome/BUILD.gn
@@ -279,9 +279,9 @@ group("child_dependencies") {
     deps += [ "//third_party/cld_2:cld2_platform_impl" ]
   }
 
-  # TODO(gyp) if (enable_nacl) {
-  #  deps += [ "<(DEPTH)/components/nacl/renderer/plugin/plugin.gyp:nacl_trusted_plugin" ]
-  #}
+  if (enable_nacl) {
+    deps += [ "//components/nacl/renderer/plugin:nacl_trusted_plugin" ]
+  }
   if (enable_remoting) {
     deps += [ "//remoting/client/plugin" ]
   }