[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_item_delegate_manager.h"
 #include "ash/shelf/shelf_model.h"
 #include "ash/shelf/shelf_util.h"
 #include "ash/shelf/shelf_window_watcher_item_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
+#include "ash/wm/window_state.h"
 #include "ash/wm/window_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/window.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/screen.h"
 
 namespace {
 
 // Sets LauncherItem property by using the value of |details|.
 void SetLauncherItemDetailsForLauncherItem(
     ash::LauncherItem* item,
     const ash::LauncherItemDetails& details) {
   item->type = details.type;
   if (details.image_resource_id != ash::kInvalidImageResourceID) {
     ResourceBundle& rb = ResourceBundle::GetSharedInstance();
     item->image = *rb.GetImageSkiaNamed(details.image_resource_id);
   }
 }
 
 // Returns true if |window| has a LauncherItem added by ShelfWindowWatcher.
 bool HasLauncherItemForWindow(aura::Window* window) {
   if (ash::GetLauncherItemDetailsForWindow(window) != NULL &&
       ash::GetLauncherIDForWindow(window) != ash::kInvalidLauncherID)
     return true;
   return false;
 }
 
+// Returns true if |window| is in the process of being dragged.
+bool IsDragging(aura::Window* window) {
+  return ash::wm::GetWindowState(window)->is_dragged();
+}
+
 }  // namespace
 
 namespace ash {
 namespace internal {
 
 ShelfWindowWatcher::RootWindowObserver::RootWindowObserver(
     ShelfWindowWatcher* window_watcher)
     : window_watcher_(window_watcher) {
 }
 
@@ skipping 86 matching lines @@
 
 void ShelfWindowWatcher::OnWindowActivated(aura::Window* gained_active,
                                            aura::Window* lost_active) {
   if (gained_active && HasLauncherItemForWindow(gained_active))
     UpdateLauncherItemStatus(gained_active, true);
   if (lost_active && HasLauncherItemForWindow(lost_active))
     UpdateLauncherItemStatus(lost_active, false);
 }
 
 void ShelfWindowWatcher::OnWindowAdded(aura::Window* window) {
-  observed_windows_.Add(window);
+  // |window| can be already observed after finishing the dragging of |window|.
+  if (!observed_windows_.IsObserving(window))
+    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.
+  // When |window| is being dragged, its parent Window is changed from default
+  // container to docked container. To handle deleting a |window| during the
+  // dragging, it is not removed from observer here. In that case, |window| will
+  // be removed from observer and its item is removed at OnWindowDestroying().
+  if (HasLauncherItemForWindow(window) && IsDragging(window))
+    return;
+
+  // Remove a child window of default container.
   if (observed_windows_.IsObserving(window))
     observed_windows_.Remove(window);
 
   if (HasLauncherItemForWindow(window))
     RemoveLauncherItem(window);
 }
 
+void ShelfWindowWatcher::OnWindowParentChanged(aura::Window* window,
+                                               aura::Window* parent) {
+  if (!parent || !HasLauncherItemForWindow(window))
+    return;
+
+  aura::Window* root_window = window->GetRootWindow();
+  aura::Window* default_container = Shell::GetContainer(
+      root_window,
+      kShellWindowId_DefaultContainer);
+  aura::Window* docked_container = Shell::GetContainer(
+      root_window,
+      kShellWindowId_DockedContainer);
+
+  // When |parent| is |default_container|, this re-parenting is already handled
+  // by OnWindowAdded().
+  // When |parent| is |docked_container|, |window| is in the process of being
+  // dragged. This case is also already handled by OnWillRemoveWindow().
+  if (parent == default_container ||
+      (parent == docked_container && IsDragging(window)))

[sky, 2013/12/17 15:49:57]

Can you just check IsDragging here and not care about dock container?

+    return;
+
+  // Remove an item when |window|'s new parent is not a docked container or
+  // a default container.
+  observed_windows_.Remove(window);
+  RemoveLauncherItem(window);
+}
+
 void ShelfWindowWatcher::OnWindowDestroying(aura::Window* window) {
   // Remove the default container.
   if (observed_windows_.IsObserving(window))
     observed_windows_.Remove(window);
+
+  // Handle removing of |window| during its dragging. See the comment in
+  // OnWillRemoveWindow().
+  if (IsDragging(window)) {
+    DCHECK(HasLauncherItemForWindow(window));

[sky, 2013/12/17 15:49:57]

Why the DCHECK here?

+    RemoveLauncherItem(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.
@@ skipping 34 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