Enable setting configuration arguments for Mojo applications with mojo_shell

mojo/examples/wget/wget.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 <stdio.h>
 
 #include "mojo/public/c/system/main.h"
 #include "mojo/public/cpp/application/application_delegate.h"
 #include "mojo/public/cpp/application/application_impl.h"
 #include "mojo/public/cpp/application/application_runner.h"
@@ skipping 54 matching lines @@
     printf("\n>>> EOF <<<\n");
   }
 };
 
 }  // namespace
 
 class WGetApp : public ApplicationDelegate {
  public:
   virtual void Initialize(ApplicationImpl* app) override {
     app->ConnectToService("mojo:mojo_network_service", &network_service_);
-    Start();
+    Start(app->args());
   }
 
  private:
-  void Start() {
-    std::string url = PromptForURL();
+  void Start(const Array<String>& args) {
+    std::string url((args.size() > 1) ? args[1].get() : PromptForURL());
     printf("Loading: %s\n", url.c_str());
 
     network_service_->CreateURLLoader(Get(&url_loader_));
 
     URLRequestPtr request(URLRequest::New());
     request->url = url;
     request->method = "GET";
     request->auto_follow_redirects = true;
 
     url_loader_->Start(request.Pass(), ResponsePrinter());
@@ skipping 11 matching lines @@
   URLLoaderPtr url_loader_;
 };
 
 }  // namespace examples
 }  // namespace mojo
 
 MojoResult MojoMain(MojoHandle shell_handle) {
   mojo::ApplicationRunner runner(new mojo::examples::WGetApp);
   return runner.Run(shell_handle);
 }