Fix races when the same bits are downloaded from 2 URLs.

shell/desktop/mojo_main.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <algorithm>
 #include <iostream>
 
 #include "base/at_exit.h"
 #include "base/base_switches.h"
 #include "base/bind.h"
@@ skipping 11 matching lines @@
   std::cerr << "Launch Mojo applications.\n";
   std::cerr
       << "Usage: mojo_shell"
       << " [--" << switches::kArgsFor << "=<mojo-app>]"
       << " [--" << switches::kContentHandlers << "=<handlers>]"
       << " [--" << switches::kEnableExternalApplications << "]"
       << " [--" << switches::kDisableCache << "]"
       << " [--" << switches::kEnableMultiprocess << "]"
       << " [--" << switches::kOrigin << "=<url-lib-path>]"
       << " [--" << switches::kURLMappings << "=from1=to1,from2=to2]"
+      << " [--" << switches::kPredictableAppFilenames << "]"
       << " [--" << switches::kWaitForDebugger << "]"
       << " <mojo-app> ...\n\n"
       << "A <mojo-app> is a Mojo URL or a Mojo URL and arguments within "
       << "quotes.\n"
       << "Example: mojo_shell \"mojo:js_standalone test.js\".\n"
       << "<url-lib-path> is searched for shared libraries named by mojo URLs.\n"
       << "The value of <handlers> is a comma separated list like:\n"
       << "text/html,mojo:html_viewer,"
       << "application/javascript,mojo:js_content_handler\n";
 }
@@ skipping 55 matching lines @@
           FROM_HERE,
           base::Bind(&mojo::shell::RunCommandLineApps, &shell_context));
       message_loop.Run();
 
       // Must be called before |message_loop| is destroyed.
       shell_context.Shutdown();
     }
   }
   return 0;
 }