aura-mus: Implement stacking in DesktopWindowTreeHostMus.

services/ui/ws/window_tree.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 "services/ui/ws/window_tree.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 1587 matching lines @@
     // The window isn't parented. There's nothing to do.
     DVLOG(1) << "DeactivateWindow failed (window unparented)";
     return;
   }
 
   WindowTree* wm_tree = display_root->window_manager_state()->window_tree();
   wm_tree->window_manager_internal_->WmDeactivateWindow(
       wm_tree->ClientWindowIdForWindow(window).id);
 }
 
+void WindowTree::StackAtTop(uint32_t change_id, Id window_id) {
+  ServerWindow* window = GetWindowByClientId(ClientWindowId(window_id));
+  if (!window) {
+    DVLOG(1) << "StackAtTop failed (invalid id)";
+    client()->OnChangeCompleted(change_id, false);
+    return;
+  }
+
+  if (!access_policy_->CanStackAtTop(window)) {
+    DVLOG(1) << "StackAtTop failed (access denied)";
+    client()->OnChangeCompleted(change_id, false);
+    return;
+  }
+
+  ServerWindow* parent = window->parent();
+  if (!parent) {
+    DVLOG(1) << "StackAtTop failed (window unparented)";
+    client()->OnChangeCompleted(change_id, false);
+    return;
+  }
+
+  DCHECK(!parent->children().empty());
+  if (parent->children().back() == window) {
+    // Ignore this call; the client didn't know they were already at the top.
+    DVLOG(3) << "StackAtTop ignored (already at top)";
+    client()->OnChangeCompleted(change_id, true);
+    return;
+  }
+
+  ServerWindow* relative_window = parent->children().back();
+  Operation op(this, window_server_, OperationType::REORDER_WINDOW);
+  window->Reorder(relative_window, mojom::OrderDirection::ABOVE);
+  window_server_->ProcessWindowReorder(window, relative_window,
+                                       mojom::OrderDirection::ABOVE);
+
+  client()->OnChangeCompleted(change_id, true);
+}
+
 void WindowTree::GetWindowManagerClient(
     mojo::AssociatedInterfaceRequest<mojom::WindowManagerClient> internal) {
   if (!access_policy_->CanSetWindowManager() || !window_manager_internal_ ||
       window_manager_internal_client_binding_) {
     return;
   }
   window_manager_internal_client_binding_.reset(
       new mojo::AssociatedBinding<mojom::WindowManagerClient>(
           this, std::move(internal)));
 }
@@ skipping 412 matching lines @@
   client()->OnCompleteDrop(client_window_id.id, event_flags, cursor_offset,
                            effect_bitmask, callback);
 }
 
 void WindowTree::PerformOnDragDropDone() {
   client()->OnDragDropDone();
 }
 
 }  // namespace ws
 }  // namespace ui