Allows menu host windows to be enumerated in DragTargetWindowFinder

ui/base/x/x11_util.cc

Index: ui/base/x/x11_util.cc
diff --git a/ui/base/x/x11_util.cc b/ui/base/x/x11_util.cc
index c71740cd0f4efd67baab29622a4ad5b680379d9c..d8bb407bd7dd5d3143e0ddbd4adc8f057eeef7d8 100644
--- a/ui/base/x/x11_util.cc
+++ b/ui/base/x/x11_util.cc
@@ -1067,6 +1067,18 @@ bool EnumerateChildren(EnumerateWindowsDelegate* delegate, XID window,
   if (depth > max_depth)
     return false;
 
+  std::vector<XID> windows;
+  std::vector<XID>::iterator iter;
+  if (depth == 0) {
+    XMenuList::GetInstance()->InsertMenuWindowXIDs(&windows);
+    // Enumerate the menus first.
+    for (iter = windows.begin(); iter != windows.end(); iter++) {
+      if (delegate->ShouldStopIterating(*iter))
+        return true;
+    }
+    windows.clear();
+  }
+
   XID root, parent, *children;
   unsigned int num_children;
   int status = XQueryTree(gfx::GetXDisplay(), window, &root, &parent, &children,
@@ -1074,7 +1086,6 @@ bool EnumerateChildren(EnumerateWindowsDelegate* delegate, XID window,
   if (status == 0)
     return false;
 
-  std::vector<XID> windows;
   for (int i = static_cast<int>(num_children) - 1; i >= 0; i--)
     windows.push_back(children[i]);
 
@@ -1082,7 +1093,6 @@ bool EnumerateChildren(EnumerateWindowsDelegate* delegate, XID window,
 
   // XQueryTree returns the children of |window| in bottom-to-top order, so
   // reverse-iterate the list to check the windows from top-to-bottom.
-  std::vector<XID>::iterator iter;
   for (iter = windows.begin(); iter != windows.end(); iter++) {
     if (IsWindowNamed(*iter) && delegate->ShouldStopIterating(*iter))
       return true;
@@ -1118,6 +1128,7 @@ void EnumerateTopLevelWindows(ui::EnumerateWindowsDelegate* delegate) {
     ui::EnumerateAllWindows(delegate, kMaxSearchDepth);
     return;
   }
+  XMenuList::GetInstance()->InsertMenuWindowXIDs(&stack);
 
   std::vector<XID>::iterator iter;
   for (iter = stack.begin(); iter != stack.end(); iter++) {
@@ -1466,6 +1477,42 @@ void XScopedCursor::reset(::Cursor cursor) {
   cursor_ = cursor;
 }
 
+// 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) {
+  std::vector<XID>::iterator iter;
+  for (iter = menus_.begin(); iter != menus_.end(); ++iter)
+    stack->insert(stack->begin(), *iter);
+}
+
 // ----------------------------------------------------------------------------
 // These functions are declared in x11_util_internal.h because they require
 // XLib.h to be included, and it conflicts with many other headers.