Aura desktop: Fix tab dragging within a single chrome window.

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 d0d0188bd8c1359de6585577b92e112a154b57fe..b058b2fe340b77e1e877279f21fc8c2077f4f360 100644
--- a/ui/base/x/x11_util.cc
+++ b/ui/base/x/x11_util.cc
@@ -769,6 +769,25 @@ bool EnumerateAllWindows(EnumerateWindowsDelegate* delegate, int max_depth) {
   return EnumerateChildren(delegate, root, max_depth, 0);
 }
 
+void EnumerateTopLevelWindows(ui::EnumerateWindowsDelegate* delegate) {
+  std::vector<XID> stack;
+  if (!ui::GetXWindowStack(ui::GetX11RootWindow(), &stack)) {
+    // Window Manager doesn't support _NET_CLIENT_LIST_STACKING, so fall back
+    // to old school enumeration of all X windows.  Some WMs parent 'top-level'
+    // windows in unnamed actual top-level windows (ion WM), so extend the
+    // search depth to all children of top-level windows.
+    const int kMaxSearchDepth = 1;
+    ui::EnumerateAllWindows(delegate, kMaxSearchDepth);
+    return;
+  }
+
+  std::vector<XID>::iterator iter;
+  for (iter = stack.begin(); iter != stack.end(); iter++) {
+    if (delegate->ShouldStopIterating(*iter))
+      return;
+  }
+}
+
 bool GetXWindowStack(Window window, std::vector<XID>* windows) {
   windows->clear();