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

ui/base/x/x11_util.cc

 // Copyright (c) 2012 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.
 
 // This file defines utility functions for X11 (Linux only). This code has been
 // ported from XCB since we can't use XCB on Ubuntu while its 32-bit support
 // remains woefully incomplete.
 
 #include "ui/base/x/x11_util.h"
 
@@ skipping 751 matching lines @@
   }
 
   return false;
 }
 
 bool EnumerateAllWindows(EnumerateWindowsDelegate* delegate, int max_depth) {
   XID root = GetX11RootWindow();
   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();
 
   Atom type;
   int format;
   unsigned long count;
   unsigned char *data = NULL;
   if (GetProperty(window,
                   "_NET_CLIENT_LIST_STACKING",
                   ~0L,
@@ skipping 477 matching lines @@
       << "request_code " << static_cast<int>(error_event.request_code) << ", "
       << "minor_code " << static_cast<int>(error_event.minor_code)
       << " (" << request_str << ")";
 }
 
 // ----------------------------------------------------------------------------
 // End of x11_util_internal.h
 
 
 }  // namespace ui