[ash] Don't remove an item when associated window is dragged

ash/shelf/shelf_window_watcher.cc

 // Copyright 2013 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/shelf/shelf_window_watcher.h"
 
 #include "ash/display/display_controller.h"
 #include "ash/shelf/shelf_model.h"
 #include "ash/shelf/shelf_util.h"
 #include "ash/shell.h"
@@ skipping 128 matching lines @@
   observed_windows_.Add(window);
   // Add LauncherItem if |window| already has a LauncherItemDetails when it is
   // created. Don't make a new LauncherItem for the re-parented |window| that
   // already has a LauncherItem.
   if (GetLauncherIDForWindow(window) == ash::kInvalidLauncherID &&
       GetLauncherItemDetailsForWindow(window))
     AddLauncherItem(window);
 }
 
 void ShelfWindowWatcher::OnWillRemoveWindow(aura::Window* window) {
-  // Remove a child window of default container and its item if it has.
+  // Remove a child window of default container.
+  if (observed_windows_.IsObserving(window))

[sky, 2013/12/12 16:41:43]

If you do this, it means you need to better track window. In particular if
window gets added to another container it should not still have an item on the
shelf. Also, there should be a way for you to detect the window is in the
process of being dragged and only special case that.

[simonhong, 2013/12/13 02:03:45]

Checked window's dragging state and if so, an item is not removed.

+    observed_windows_.Remove(window);
+}
+
+void ShelfWindowWatcher::OnWindowDestroying(aura::Window* window) {
+  // Remove the default container.
   if (observed_windows_.IsObserving(window))
     observed_windows_.Remove(window);
 
   if (HasLauncherItemForWindow(window))
     RemoveLauncherItem(window);
 }
 
-void ShelfWindowWatcher::OnWindowDestroying(aura::Window* window) {
-  // Remove the default container.
-  if (observed_windows_.IsObserving(window))
-    observed_windows_.Remove(window);
-}
-
 void ShelfWindowWatcher::OnWindowPropertyChanged(aura::Window* window,
                                                  const void* key,
                                                  intptr_t old) {
   if (key != kLauncherItemDetailsKey)
     return;
 
   if (GetLauncherItemDetailsForWindow(window) == NULL) {
     // Removes LauncherItem for |window| when it has a LauncherItem.
     if (reinterpret_cast<LauncherItemDetails*>(old) != NULL)
       RemoveLauncherItem(window);
@@ skipping 32 matching lines @@
 
 void ShelfWindowWatcher::OnDisplayRemoved(const gfx::Display& old_display) {
   // When this is called, RootWindow of |old_display| is already removed.
   // Instead, we remove an observer from RootWindow and ActivationClient in the
   // OnRootWindowDestroyed().
   // Do nothing here.
 }
 
 }  // namespace internal
 }  // namespace ash