Enables specifying mojo url mapping on command line

mojo/shell/switches.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 "mojo/shell/switches.h"
 
 namespace switches {
 
 // Specify configuration arguments for a Mojo application URL. For example:
 // --args-for='mojo://mojo_wget http://www.google.com'
@@ skipping 25 matching lines @@
 const char kHelp[] = "help";
 
 // Map mojo: URLs to a shared library of similar name at this origin. See
 // mojo_url_resolver.cc for details.
 const char kOrigin[] = "origin";
 
 // Enables the mojo spy, which acts as a man-in-the-middle inspector for
 // message pipes and other activities. This is work in progress.
 const char kSpy[] = "spy";
 
+// Specifies a set of mappings to apply when resolving urls. The value is set of
+// ',' separated mappings, where each mapping consists of a pair of urls giving
+// the to/from url to map. For example, 'a=b,c=d' contains two mappings, the
+// first maps 'a' to 'b' and the second 'c' to 'd'.
+const char kURLMappings[] = "url-mappings";
+
 }  // namespace switches