Various mojom cleanup from ContentHandler changes.

mojo/services/public/interfaces/navigation/navigation.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/services/public/interfaces/network/url_loader.mojom"
 
 module mojo {
 
 // Expresses a preference for where a navigation will be performed.
 enum Target {
   // No preference
   DEFAULT,
 
   // In the same ViewManager node that the navigation was initiated
   SOURCE_NODE,
 
   // In a new ViewManager node
   NEW_NODE
 };
 
-struct NavigationDetails {
-  // TODO(mpcomplete): will we ever need more than the URLRequest? Can
-  // we pass that around directly?
-  URLRequest? request = default;
-};
-
-struct ResponseDetails {
-  // TODO(beng): consider providing access to URLRequest too. Currently it is
-  //             not possible to obtain from the URLLoader.
-
-  URLResponse? response;
-
-  // The URLLoader instance that generated the response. This must be kept
-  // alive until the response body has been completely consumed.
-  URLLoader? loader;
-};
-
 // Embedders that support navigation of implement this interface.
 interface NavigatorHost {
-  RequestNavigate(Target target, NavigationDetails? details);
+  RequestNavigate(Target target, URLRequest request);
 
   // Applications call this to inform hosts of navigations they performed
   // locally. For example, pushState() navigations in an HTML application.
-  DidNavigateLocally(string? url);
+  DidNavigateLocally(string url);
 };
 
 }