DesktopAura: Track windows "owned" via the DesktopWindowTreeHost

ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
index 5eb0d546515ee37a17bba5c867d3f36b7aa4465a..ed892f88d822986e3dcb706c4234e2221e10f334 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
@@ -481,6 +481,21 @@ bool DesktopWindowTreeHostWin::ShouldUseDesktopNativeCursorManager() const {
   return true;
 }
 
+std::vector<DesktopWindowTreeHost*>
+DesktopWindowTreeHostWin::GetOwnedTopLevelHosts() const {
+  std::vector<DesktopWindowTreeHost*> hosts;
+  std::vector<HWND> child_windows = message_handler_->GetOwnedWindows();
+  for (HWND hwnd : child_windows) {
+    if (aura::WindowTreeHost* host = GetForAcceleratedWidget(hwnd)) {
+      if (DesktopWindowTreeHostWin* target =
+              host->window()->GetProperty(kDesktopWindowTreeHostKey)) {
+        hosts.push_back(target);
+      }
+    }
+  }
+  return hosts;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopWindowTreeHostWin, WindowTreeHost implementation: