Fixes stale icon during reparent drag out of a folder

Bug: 868117
Change-Id: I15aae661ae200ec858e6886be718eaa55ff3266a
Reviewed-on: https://chromium-review.googlesource.com/1152231
Commit-Queue: Kevin Strohbehn <ginko@google.com>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Reviewed-by: Weidong Guo <weidongg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579655}

ash/app_list/model/app_list_folder_item.cc

@@ -70,4 +70,8 @@ void AppListFolderItem::OnFolderImageUpdated() {
   SetIcon(folder_image_.icon());
 }
 
+void AppListFolderItem::NotifyOfDraggedItem(AppListItem* dragged_item) {
+  folder_image_.UpdateDraggedItem(dragged_item);
+}
+
 }  // namespace app_list

ash/app_list/model/app_list_folder_item.h

@@ -73,6 +73,10 @@ class APP_LIST_MODEL_EXPORT AppListFolderItem : public AppListItem,
   // FolderImageObserver overrides:
   void OnFolderImageUpdated() override;
 
+  // Informs the folder item of an item being dragged, that it may notify its
+  // image.
+  void NotifyOfDraggedItem(AppListItem* dragged_item);
+
  private:
   // The type of folder; may affect behavior of folder views.
   const FolderType folder_type_;

ash/app_list/model/folder_image.cc

@@ -163,15 +163,26 @@ void FolderImage::UpdateIcon() {
     item->RemoveObserver(this);
   top_items_.clear();
 
-  for (size_t i = 0; i < std::min(kNumFolderTopItems, item_list_->item_count());
+  for (size_t i = 0;
+       i < item_list_->item_count() && top_items_.size() < kNumFolderTopItems;
        ++i) {
     AppListItem* item = item_list_->item_at(i);
+    // If this item is currently being dragged, pretend it has already left our
+    // folder
+    if (item == dragged_item_)
+      continue;
     item->AddObserver(this);
     top_items_.push_back(item);
   }
   RedrawIconAndNotify();
 }
 
+void FolderImage::UpdateDraggedItem(const AppListItem* dragged_item) {
+  DCHECK(dragged_item_ != dragged_item);
+  dragged_item_ = dragged_item;
+  UpdateIcon();
+}
+
 // static
 std::vector<gfx::Rect> FolderImage::GetTopIconsBounds(
     const gfx::Rect& folder_icon_bounds,

ash/app_list/model/folder_image.h

@@ -52,6 +52,10 @@ class APP_LIST_MODEL_EXPORT FolderImage : public AppListItemListObserver,
   // and notifies observers that the icon has changed.
   void UpdateIcon();
 
+  // Given an AppListItem currently being dragged, updates |dragged_item_| then
+  // executes an ordinary run of UpdateIcon()
+  void UpdateDraggedItem(const AppListItem* dragged_item);
+
   const gfx::ImageSkia& icon() const { return icon_; }
 
   // Calculates the top item icons' bounds inside |folder_icon_bounds|.
@@ -96,6 +100,9 @@ class APP_LIST_MODEL_EXPORT FolderImage : public AppListItemListObserver,
   // List of top-level app list items (to display small in the icon).
   AppListItemList* item_list_;
 
+  // Item being dragged, if any.
+  const AppListItem* dragged_item_ = nullptr;
+
   // Top items for generating folder icon.
   std::vector<AppListItem*> top_items_;
 

ash/app_list/views/app_list_folder_view.cc

@@ -728,6 +728,9 @@ void AppListFolderView::ReparentItem(
   gfx::Point to_root_level_grid = drag_point_in_folder_grid;
   ConvertPointToTarget(items_grid_view_, container_view_->apps_grid_view(),
                        &to_root_level_grid);
+  // Ensures the icon updates to reflect that the icon has been removed during
+  // the drag
+  folder_item_->NotifyOfDraggedItem(original_drag_view->item());
   StartSetupDragInRootLevelAppsGridView(original_drag_view, to_root_level_grid,
                                         has_native_drag);
   container_view_->ReparentFolderItemTransit(folder_item_);

ash/app_list/views/apps_grid_view.cc

@@ -1629,6 +1629,10 @@ void AppsGridView::EndDragFromReparentItemInRootLevel(
   if (!drag_view_)
     return;
 
+  DCHECK(activated_folder_item_view_);
+  static_cast<AppListFolderItem*>(activated_folder_item_view_->item())
+      ->NotifyOfDraggedItem(nullptr);
+
   DCHECK(IsDraggingForReparentInRootLevelGridView());
   bool cancel_reparent = cancel_drag || drop_attempt_ == DROP_FOR_NONE;
   if (!events_forwarded_to_drag_drop_host && !cancel_reparent) {