mojo: make NetworkServiceImpl clean up after itself

mojo/services/network/main.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 "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/message_loop/message_loop.h"
 #include "mojo/public/cpp/application/application_connection.h"
@@ skipping 48 matching lines @@
   scoped_ptr<mojo::NetworkContext> context_;
 };
 
 extern "C" APPLICATION_EXPORT MojoResult CDECL MojoMain(
     MojoHandle shell_handle) {
   base::CommandLine::Init(0, NULL);
 #if !defined(COMPONENT_BUILD)
   base::AtExitManager at_exit;
 #endif
 
+  // The Delegate owns the NetworkContext, which needs to outlive
+  // MessageLoopForIO. Destruction of the message loop will serve to
+  // invalidate connections made to network services (URLLoader) and cause
+  // the service instances to be cleaned up as a result of observing pipe
+  // errors. This is important as ~URLRequestContext asserts that no out-
+  // standing URLRequests exist.
+  Delegate delegate;

[darin (slow to review), 2014/07/19 03:54:44]

I might call out the scoping a bit more explicitly for readability sake:

  Delegate delegate;
  {
    // ...
    base::MessageLoopForIO loop;
    ...
    loop.Run();
  }

+
   // The IO message loop allows us to use net::URLRequest on this thread.
   base::MessageLoopForIO loop;
 
-  Delegate delegate;
   mojo::ApplicationImpl app(
       &delegate, mojo::MakeScopedHandle(mojo::MessagePipeHandle(shell_handle)));
 
   loop.Run();
   return MOJO_RESULT_OK;
 }