First cut at "content handling" support in Mojo.

mojo/services/public/interfaces/content_handler/content_handler.mojom

 // 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.
 
 import "mojo/public/interfaces/application/service_provider.mojom"
+import "mojo/services/public/interfaces/network/url_loader.mojom"
 
 module mojo {
 
-// Applications vend Services through the ServiceProvider interface. Services
-// implement Interfaces.
-[Client=Shell]
-interface Application {
-  AcceptConnection(string requestor_url, ServiceProvider provider);
+interface ContentHandler {

[darin (slow to review), 2014/08/06 23:10:02]

by the way, I'm not 100% sold on the name "OnConnect". it doesn't seem to go
with ContentHandler. I get the relationship with ConnectToApplication, so I
guess it works. Maybe we need to think more about these names. That can happen
after this CL lands too.

[Aaron Boodman, 2014/08/07 00:03:12]

Yeah. I am not 100% with it either. There is also the issue that in the future,
I think we will want to invoke this interface but not actually pass content in
order to handle offline applications.

For example I imagine that apps will be able to tell the system that they can
handle a URL space. In that case, when we connect to them, we might end up
calling this interface, but not doing a network request.

I think this is really more of a DelegatedApplication or something. But I
figured I'd let it be for now and probably things would become more clear as we
move forward.

+  OnConnect(string url,

[darin (slow to review), 2014/08/06 23:10:02]

Isn't this |url| parameter redundant? The URLResponse should have an identical
|url| field.

[Aaron Boodman, 2014/08/07 00:03:12]

No, because redirects. Also, as I said above in the future we might not pass
|response| here.

+            URLResponse url_response,
+            ServiceProvider service_provider);
 };
 
 }