Allows menu host windows to be enumerated in DragTargetWindowFinder

ui/base/x/x11_menu_list.cc

Index: ui/base/x/x11_menu_list.cc
diff --git a/ui/base/x/x11_menu_list.cc b/ui/base/x/x11_menu_list.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3396e57840edc352b244cd231bbbfc4bf29825f6
--- /dev/null
+++ b/ui/base/x/x11_menu_list.cc
@@ -0,0 +1,46 @@
+// Copyright (c) 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 "ui/base/x/x11_menu_list.h"
+
+#include "base/memory/singleton.h"
+#include "ui/base/x/x11_util.h"
+
+namespace ui {
+
+// static
+XMenuList* XMenuList::GetInstance() {
+  return Singleton<XMenuList>::get();
+}
+
+XMenuList::XMenuList()
+    : menu_type_atom_(GetAtom("_NET_WM_WINDOW_TYPE_MENU")) {
+}
+
+XMenuList::~XMenuList() {
+  menus_.clear();
+}
+
+void XMenuList::MaybeRegisterMenu(XID menu) {
+  int value = 0;
+  if (!GetIntProperty(menu, "_NET_WM_WINDOW_TYPE", &value) ||
+      static_cast<Atom>(value) != menu_type_atom_) {
+    return;
+  }
+  menus_.push_back(menu);
+}
+
+void XMenuList::MaybeUnregisterMenu(XID menu) {
+  std::vector<XID>::iterator iter = std::find(menus_.begin(), menus_.end(),
+                                              menu);
+  if (iter == menus_.end())
+    return;
+  menus_.erase(iter);
+}
+
+void XMenuList::InsertMenuWindowXIDs(std::vector<XID>* stack) {
+  stack->insert(stack->begin(), menus_.begin(), menus_.end());
+}
+
+}  // namespace ui