Simplify some mojo_shell code.

mojo/shell/switches.cc

Index: mojo/shell/switches.cc
diff --git a/mojo/shell/switches.cc b/mojo/shell/switches.cc
index 6aa5cdadf46748aec5c79d27c89ac29e93deef82..2150b1970102ca93fb957fdd7179c86883525172 100644
--- a/mojo/shell/switches.cc
+++ b/mojo/shell/switches.cc
@@ -35,11 +35,6 @@ const char kDisableCache[] = "disable-cache";
 // If set apps downloaded are not deleted.
 const char kDontDeleteOnDownload[] = "dont-delete-on-download";
 
-// Allow externally-running applications to discover, connect to, and register
-// themselves with the shell.
-// TODO(cmasone): Work in progress. Once we're sure this works, remove.
-const char kEnableExternalApplications[] = "enable-external-applications";
-
 // Load apps in separate processes.
 // TODO(vtl): Work in progress; doesn't work. Flip this to "disable" (or maybe
 // change it to "single-process") when it works.
@@ -85,7 +80,6 @@ const char* kSwitchArray[] = {kV,
                               kContentHandlers,
                               kDisableCache,
                               kDontDeleteOnDownload,
-                              kEnableExternalApplications,
                               kEnableMultiprocess,
                               kForceInProcess,
                               kHelp,