mus: Allow embedder to intercept events.

components/mus/public/interfaces/window_tree.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.
 
 module mus.mojom;
 
 import "cc/ipc/surface_id.mojom";
 import "components/mus/public/interfaces/cursor.mojom";
 import "components/mus/public/interfaces/event_matcher.mojom";
 import "components/mus/public/interfaces/mus_constants.mojom";
@@ skipping 159 matching lines @@
 
   // A connection may grant access to another connection by way of Embed().
   // Embed() results in the supplied WindowTreeClient being configured with a
   // root window of |window_id|. The supplied WindowTreeClient may create child
   // windows and do other various tree operations (including Embed()), but does
   // not see nor have access to any of the windows above the embed point.
   //
   // The caller must have created |window_id|. If not the request fails and the
   // response is false.
   //
+  // The embedder can dictate the behaviour of the embedded client by setting
+  // the appropriate embed flags (e.g. kEmbedFlagEmbedderInterceptsEvents).
+  //
   // When a connection embeds a WindowTreeClient the originating connection no
   // longer has privileges to access or see any of the children of the window.
   // If the window had existing children the children are removed. The
   // WindowManager gets to see the whole tree.
   //
   // A window may only have one embedding in it at a time. Subsequent calls to
   // Embed() for the same window result in the currently embedded
   // WindowTreeClient being removed. The embedded app is told this by way of
   // OnUnembed(), which is followed by OnWindowDeleted() (as the connection no
   // longer has access to the window).
   //
   // The embedder can detect when the embedded app disconnects by way of
   // OnEmbeddedAppDisconnected().
   //
   // The callback returns whether the embedding was successful.
-  Embed(uint32 window_id, WindowTreeClient client) => (bool success);
+  Embed(uint32 window_id, WindowTreeClient client, uint32 embed_flags)
+      => (bool success);
 
   // Sets focus to the specified window, use 0 to clear focus. For a window to
   // get focus the following has to happen: the window is drawn, the window has
   // been marked as focusable (see SetCanFocus()) and the window is in a
   // container the WindowManager has identified as allowing activation
   // (see WindowManagerClient::AddActivationParent()).
   SetFocus(uint32 change_id, uint32 window_id);
 
   // Marks the specified window as being able to receive focus.
   SetCanFocus(uint32 window_id, bool can_focus);
@@ skipping 159 matching lines @@
   // See description of WindowManager for details.
   GetWindowManager(associated WindowManager& internal);
 };
 
 // Mus provides this interface as a way for clients to connect and obtain a
 // WindowTree handle with a supplied WindowTreeClient handle. The
 // WindowTreeClient has no roots, use NewTopLevelWindow() to create one.
 interface WindowTreeFactory {
   CreateWindowTree(WindowTree& tree_request, WindowTreeClient client);
 };