Adds remainder of support for multiple roots to WS

components/mus/public/cpp/lib/window.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 "components/mus/public/cpp/window.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <set>
@@ skipping 129 matching lines @@
   Window* window_;
   const gfx::Rect old_bounds_;
   const gfx::Rect new_bounds_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(ScopedSetBoundsNotifier);
 };
 
 // Some operations are only permitted in the connection that created the window.
 bool OwnsWindow(WindowTreeConnection* connection, Window* window) {
   return !connection ||
-         static_cast<WindowTreeClientImpl*>(connection)
-             ->OwnsWindow(window->id());
+         static_cast<WindowTreeClientImpl*>(connection)->OwnsWindow(window);
 }
 
 bool IsConnectionRoot(Window* window) {
   return window->connection() &&
          window->connection()->GetRoots().count(window) > 0;
 }
 
 bool OwnsWindowOrIsRoot(Window* window) {
   return OwnsWindow(window->connection(), window) || IsConnectionRoot(window);
 }
@@ skipping 105 matching lines @@
   for (const Window* parent = this; parent; parent = parent->parent())
     root = parent;
   return root;
 }
 
 void Window::AddChild(Window* child) {
   // TODO(beng): not necessarily valid to all connections, but possibly to the
   //             embeddee in an embedder-embeddee relationship.
   if (connection_)
     CHECK_EQ(child->connection(), connection_);
+  // Roots can not be added as children of other windows.
+  if (tree_client() && tree_client()->IsRoot(child))
+    return;
   LocalAddChild(child);
   if (connection_)
     tree_client()->AddChild(this, child->id());
 }
 
 void Window::RemoveChild(Window* child) {
   // TODO(beng): not necessarily valid to all connections, but possibly to the
   //             embeddee in an embedder-embeddee relationship.
   if (connection_)
     CHECK_EQ(child->connection(), connection_);
@@ skipping 516 matching lines @@
     notifier->NotifyWindowReordered();
 
   return true;
 }
 
 // static
 Window** Window::GetStackingTarget(Window* window) {
   return &window->stacking_target_;
 }
 }  // namespace mus