Inform window manager about modal windows in mus+ash.

services/ui/ws/window_tree.cc

Index: services/ui/ws/window_tree.cc
diff --git a/services/ui/ws/window_tree.cc b/services/ui/ws/window_tree.cc
index 8602975133cad3c06da70455c4e44c282aa2d9d3..9875dd7a638d00de31d97e8ceb57554f36feacb2 100644
--- a/services/ui/ws/window_tree.cc
+++ b/services/ui/ws/window_tree.cc
@@ -352,9 +352,7 @@ bool WindowTree::DeleteWindow(const ClientWindowId& window_id) {
   return tree && tree->DeleteWindowImpl(this, window);
 }
 
-bool WindowTree::SetModalType(const ClientWindowId& window_id,
-                              ModalType modal_type) {
-  ServerWindow* window = GetWindowByClientId(window_id);
+bool WindowTree::SetModalType(ServerWindow* window, ModalType modal_type) {
   if (!window || !access_policy_->CanSetModal(window))
     return false;
 
@@ -1295,8 +1293,17 @@ void WindowTree::RemoveTransientWindowFromParent(uint32_t change_id,
 void WindowTree::SetModalType(uint32_t change_id,
                               Id window_id,
                               ModalType modal_type) {
-  client()->OnChangeCompleted(
-      change_id, SetModalType(ClientWindowId(window_id), modal_type));
+  ServerWindow* window = GetWindowByClientId(ClientWindowId(window_id));
+  if (window && ShouldRouteToWindowManager(window)) {
+    WindowTree* wm_tree = GetWindowManagerDisplayRoot(window)

[sky, 2017/03/14 21:16:22]

As ash always allows the change I suggest you forward the change to ash, but
don't require a return value.

[Hadi, 2017/03/17 16:16:32]

Done. I also moved the forwarding part to the other overload of SetModalType()
so I can test forwarding in window_tree_unittest.

+                              ->window_manager_state()
+                              ->window_tree();
+    wm_tree->window_manager_internal_->WmSetModalType(
+        window_server_->GenerateWindowManagerChangeId(this, change_id),

[sky, 2017/03/14 21:16:23]

If you generate a change id like this the expectation is that the window manager
would ack the change id. You don't have that here. Follow the pattern used in
SetCanFocus.

[Hadi, 2017/03/17 16:16:32]

Done.

+        wm_tree->ClientWindowIdForWindow(window).id, modal_type);
+    return;
+  }
+  client()->OnChangeCompleted(change_id, SetModalType(window, modal_type));
 }
 
 void WindowTree::ReorderWindow(uint32_t change_id,