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

mojo/shell/mojo_url_resolver.cc

 // 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.
 
 #include "mojo/shell/mojo_url_resolver.h"
 
 #include "base/base_paths.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
@@ skipping 15 matching lines @@
   NOTREACHED() << "dynamic loading of services not supported";
   return std::string();
 #endif
 }
 
 }  // namespace
 
 MojoURLResolver::MojoURLResolver() {
   // Needed to treat first component of mojo URLs as host, not path.
   url::AddStandardScheme("mojo");
+
+  // By default, resolve mojo URLs to files living alongside the shell.
+  base::FilePath path;
+  PathService::Get(base::DIR_MODULE, &path);
+  origin_ = net::FilePathToFileURL(path).spec();

[tim (not reviewing), 2014/07/23 22:22:32]

As we were talking about, probably makes sense to unify the local_file_set code
with this, since it is also providing the same "default value" for local files. 
Then, local_file_set would be there to force looking in DIR_MODULE for
registered mojo: urls, even if a BaseURL is set on the resolver.

 }
 
 MojoURLResolver::~MojoURLResolver() {
 }
 
 void MojoURLResolver::AddCustomMapping(const GURL& mojo_url,
                                        const GURL& resolved_url) {
   url_map_[mojo_url] = resolved_url;
 }
 
@@ skipping 15 matching lines @@
     path = path.Append(base::FilePath::FromUTF8Unsafe(lib));
     return net::FilePathToFileURL(path);
   }
 
   // Otherwise, resolve to an URL relative to origin_.
   return GURL(origin_ + "/" + lib);
 }
 
 }  // namespace shell
 }  // namespace mojo