Mojo: Set a default value for the --origin command line switch.

mojo/shell/mojo_url_resolver.h

 // Copyright 2014 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.
 
 #ifndef MOJO_SHELL_MOJO_URL_RESOLVER_H_
 #define MOJO_SHELL_MOJO_URL_RESOLVER_H_
 
 #include <map>
 #include <set>
 
@@ skipping 13 matching lines @@
   // If specified, then unknown "mojo:" URLs will be resolved relative to this
   // base URL. That is, the portion after the colon will be appeneded to
   // |base_url| with platform-specific shared library prefix and suffix
   // inserted.
   void SetBaseURL(const GURL& base_url);
 
   // Add a custom mapping for a particular "mojo:" URL.
   void AddCustomMapping(const GURL& mojo_url, const GURL& resolved_url);
 
   // Add a local file mapping for a particular "mojo:" URL. This causes the
-  // "mojo:" URL to be resolved to an base::DIR_EXE-relative shared library.
+  // "mojo:" URL to be resolved to a base::DIR_MODULE-relative shared library.
   void AddLocalFileMapping(const GURL& mojo_url);
 
   // Resolve the given "mojo:" URL to the URL that should be used to fetch the
   // code for the corresponding Mojo App.
   GURL Resolve(const GURL& mojo_url) const;
 
  private:
   std::map<GURL, GURL> url_map_;
   std::set<GURL> local_file_set_;
+  GURL default_base_url_;
   GURL base_url_;
 };
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_MOJO_URL_RESOLVER_H_