Change type of drag-drop window to popup

ash/drag_drop/drag_drop_tracker.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.
 
 #include "ash/drag_drop/drag_drop_tracker.h"
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/coordinate_conversion.h"
 #include "ui/aura/client/window_tree_client.h"
@@ skipping 24 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(CaptureWindowActivationDelegate);
 };
 
 // Creates a window for capturing drag events.
 aura::Window* CreateCaptureWindow(aura::Window* context_root,
                                   aura::WindowDelegate* delegate) {
   static CaptureWindowActivationDelegate* activation_delegate_instance = NULL;
   if (!activation_delegate_instance)
     activation_delegate_instance = new CaptureWindowActivationDelegate;
   aura::Window* window = new aura::Window(delegate);
-  window->SetType(ui::wm::WINDOW_TYPE_NORMAL);
+  window->SetType(ui::wm::WINDOW_TYPE_POPUP);

[sky, 2014/08/19 22:05:48]

Add a comment as to why popup is desirable.

[mohsen, 2014/08/20 00:58:56]

Done.

   window->Init(aura::WINDOW_LAYER_NOT_DRAWN);
   aura::client::ParentWindowWithContext(window, context_root, gfx::Rect());
   aura::client::SetActivationDelegate(window, activation_delegate_instance);
   window->Show();
   DCHECK(window->bounds().size().IsEmpty());
   return window;
 }
 
 }  // namespace
 
@@ skipping 37 matching lines @@
       &target_root_location);
   return new ui::MouseEvent(event.type(),
                             target_location,
                             target_root_location,
                             event.flags(),
                             static_cast<const ui::MouseEvent&>(event).
                                 changed_button_flags());
 }
 
 }  // namespace ash