First cut at "content handling" support in Mojo.

mojo/shell/dbus_service_loader_linux.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 "mojo/shell/dbus_service_loader_linux.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/location.h"
@@ skipping 132 matching lines @@
   dbus::Bus::Options options;
   options.bus_type = dbus::Bus::SESSION;
   options.dbus_task_runner = context_->task_runners()->io_runner();
   bus_ = new dbus::Bus(options);
 }
 
 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()) {
+    return;
+  }
+
   DCHECK(url.SchemeIs("dbus"));
   DCHECK(url_to_load_context_.find(url) == url_to_load_context_.end());
   url_to_load_context_[url] =
       new LoadContext(this, bus_, url, shell_handle.Pass());
 }
 
 void DBusServiceLoader::OnServiceError(ServiceManager* manager,
                                        const GURL& url) {
   // TODO(cmasone): Anything at all in this method here.
 }
 
 void DBusServiceLoader::ForgetService(const GURL& url) {
   DCHECK(context_->task_runners()->shell_runner()->BelongsToCurrentThread());
   DVLOG(2) << "Forgetting service (url: " << url << ")";
 
   LoadContextMap::iterator it = url_to_load_context_.find(url);
   DCHECK(it != url_to_load_context_.end()) << url;
 
   LoadContext* doomed = it->second;
   url_to_load_context_.erase(it);
 
   delete doomed;
 }
 
 }  // namespace shell
 }  // namespace mojo