Fixs bug in notifying clients about hierarchy changes

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 567 matching lines @@
 
   client()->OnWindowSharedPropertyChanged(client_window_id.id, String(name),
                                           std::move(data));
 }
 
 void WindowTree::ProcessWindowHierarchyChanged(const ServerWindow* window,
                                                const ServerWindow* new_parent,
                                                const ServerWindow* old_parent,
                                                bool originated_change) {
   const bool knows_new = new_parent && IsWindowKnown(new_parent);
-  if (originated_change && !IsWindowKnown(window) && knows_new) {
-    std::vector<const ServerWindow*> unused;
-    GetUnknownWindowsFrom(window, &unused);
-  }
   if (originated_change || (window_server_->current_operation_type() ==
                             OperationType::DELETE_WINDOW) ||
       (window_server_->current_operation_type() == OperationType::EMBED) ||
       window_server_->DidTreeMessageClient(id_)) {
     return;
   }
 
   if (!access_policy_->ShouldNotifyOnHierarchyChange(window, &new_parent,
                                                      &old_parent)) {
     return;
@@ skipping 290 matching lines @@
   DCHECK(window);
   DCHECK_EQ(window->id().client_id, id_);
   Operation op(source, window_server_, OperationType::DELETE_WINDOW);
   delete window;
   return true;
 }
 
 void WindowTree::GetUnknownWindowsFrom(
     const ServerWindow* window,
     std::vector<const ServerWindow*>* windows) {
-  if (IsWindowKnown(window) || !access_policy_->CanGetWindowTree(window))
+  if (!access_policy_->CanGetWindowTree(window))
     return;
+
+  // This function is called in the context of a hierarchy change when the
+  // parent wasn't known. We need to tell the client about the window so that
+  // it can set the parent correctly.
   windows->push_back(window);
+  if (IsWindowKnown(window))
+    return;
+
   // There are two cases where this gets hit:
   // . During init, in which case using the window id as the client id is
   //   fine.
   // . When a window is moved to a parent of a window we know about. This is
   //   only encountered for the WM or embed roots. We assume such clients want
   //   to see the real id of the window and are only created ClientWindowIds
   //   with the client_id.
   const ClientWindowId client_window_id(WindowIdToTransportId(window->id()));
   DCHECK_EQ(0u, client_id_to_window_id_map_.count(client_window_id));
   client_id_to_window_id_map_[client_window_id] = window->id();
@@ skipping 1032 matching lines @@
   client()->OnCompleteDrop(client_window_id.id, event_flags, cursor_offset,
                            effect_bitmask, callback);
 }
 
 void WindowTree::PerformOnDragDropDone() {
   client()->OnDragDropDone();
 }
 
 }  // namespace ws
 }  // namespace ui