mus: Server-side implementation of modal windows

components/mus/ws/window_tree_impl.cc

Index: components/mus/ws/window_tree_impl.cc
diff --git a/components/mus/ws/window_tree_impl.cc b/components/mus/ws/window_tree_impl.cc
index f144d3ad60930d06e3a3a554adb700ffdf16a8fb..b57cfd7ded361e705c599be51e1dba3b3a4c362d 100644
--- a/components/mus/ws/window_tree_impl.cc
+++ b/components/mus/ws/window_tree_impl.cc
@@ -228,6 +228,16 @@ bool WindowTreeImpl::AddTransientWindow(
   return false;
 }
 
+bool WindowTreeImpl::SetAsModal(const ClientWindowId& window_id) {
+  ServerWindow* window = GetWindowByClientId(window_id);

[sky, 2016/03/02 18:28:33]

Add to the access policy where this operation is allowed. We should route it to
the wm as necessary. Basically look at something like
WindowTreeImpl::SetWindowBounds. We want that same logic here.

[mohsen, 2016/03/03 22:54:59]

Added to the access policy. However, do we also need to route this to the window
manager like SetWindowBounds? It seems to me that SetAsModal is more like
AddTransientWidnow rather than SetWindowBounds.

[sky, 2016/03/03 23:50:39]

Seems like we want clients making any random window system modal. Routing to the
windowmanager could protected against that.

[mohsen, 2016/03/04 16:24:17]

I see. I plan to implement modal systems in a follow-up patch (See the TODO I've
added in window_tree.mojom)

+  if (window) {
+    Operation op(this, connection_manager_, OperationType::SET_AS_MODAL);

[sky, 2016/03/02 18:28:33]

As you don't send any sort of notification out you don't need to create an
operation.

[mohsen, 2016/03/03 22:54:59]

Right. Removed.

+    window->SetAsModal();
+    return true;
+  }
+  return false;
+}
+
 std::vector<const ServerWindow*> WindowTreeImpl::GetWindowTree(
     const ClientWindowId& window_id) const {
   const ServerWindow* window = GetWindowByClientId(window_id);
@@ -980,6 +990,10 @@ void WindowTreeImpl::RemoveTransientWindowFromParent(uint32_t change_id,
   client_->OnChangeCompleted(change_id, success);
 }
 
+void WindowTreeImpl::SetAsModal(uint32_t change_id, Id window_id) {
+  client_->OnChangeCompleted(change_id, SetAsModal(ClientWindowId(window_id)));
+}
+
 void WindowTreeImpl::ReorderWindow(uint32_t change_id,
                                    Id window_id,
                                    Id relative_window_id,