First cut at "content handling" support in Mojo.

mojo/shell/dbus_service_loader_linux.cc

Index: mojo/shell/dbus_service_loader_linux.cc
diff --git a/mojo/shell/dbus_service_loader_linux.cc b/mojo/shell/dbus_service_loader_linux.cc
index af4e0d4422ed058d9ef7c52552218c0e01d46b87..af0556d09eac46b975c75311a8015831eeb9df2d 100644
--- a/mojo/shell/dbus_service_loader_linux.cc
+++ b/mojo/shell/dbus_service_loader_linux.cc
@@ -150,9 +150,17 @@ DBusServiceLoader::~DBusServiceLoader() {
   DCHECK(url_to_load_context_.empty());
 }
 
-void DBusServiceLoader::LoadService(ServiceManager* manager,
-                                    const GURL& url,
-                                    ScopedMessagePipeHandle shell_handle) {
+void DBusServiceLoader::LoadService(
+    ServiceManager* manager,
+    const GURL& url,
+    scoped_refptr<LoadServiceCallbacks> callbacks) {
+  // TODO(aa): This could be delayed until later, when we know that loading is
+  // going to succeed.
+  ScopedMessagePipeHandle shell_handle = callbacks->RegisterApplication();
+  if (!shell_handle.is_valid()) {

[DaveMoore, 2014/08/06 20:50:46]

Nit: no braces

[Aaron Boodman, 2014/08/06 22:49:29]

Done.

+    return;
+  }
+
   DCHECK(url.SchemeIs("dbus"));
   DCHECK(url_to_load_context_.find(url) == url_to_load_context_.end());
   url_to_load_context_[url] =