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

mojo/shell/mojo_url_resolver.cc

Index: mojo/shell/mojo_url_resolver.cc
diff --git a/mojo/shell/mojo_url_resolver.cc b/mojo/shell/mojo_url_resolver.cc
index daa91639ecc6186d23573c505471a43fb451d362..58cc101bb2c3c51e0fdd30d43d294174f698f38c 100644
--- a/mojo/shell/mojo_url_resolver.cc
+++ b/mojo/shell/mojo_url_resolver.cc
@@ -33,6 +33,11 @@ std::string MakeSharedLibraryName(const std::string& host_name) {
 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() {