Implement ui for re-parenting an item from an app list folder to another position or folder in the …

ui/app_list/views/folder_background_view.h

+// Copyright 2014 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.
+
+#ifndef UI_APP_LIST_VIEWS_FOLDER_BACKGROUND_VIEW_H_
+#define UI_APP_LIST_VIEWS_FOLDER_BACKGROUND_VIEW_H_
+
+#include "ui/compositor/layer_animation_observer.h"
+#include "ui/views/view.h"
+
+namespace app_list {
+
+class AppListFolderView;
+
+// Draws the ink bubble indicating the boundary of the folder when user drags an
+// item inside a folder.
+class FolderBackgroundView : public views::View,
+                             public ui::ImplicitAnimationObserver {
+ public:
+  enum ShowState {
+    NO_BUBBLE,
+    SHOW_BUBBLE,
+    HIDE_BUBBLE,
+  };
+
+  FolderBackgroundView();
+  virtual ~FolderBackgroundView();
+
+  // Updates the ink bubble's ShowState.
+  void UpdateFolderContainerBubble(ShowState state);
+
+  // Returns the radius of the folder container ink bubble.
+  int GetFolderContainerBubbleRadius() const;
+
+  void set_folder_view(AppListFolderView* folder_view) {
+    folder_view_ = folder_view;
+  }
+
+ private:
+  // views::View overrides:
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
+
+  // ui::ImplicitAnimationObserver overrides:
+  virtual void OnImplicitAnimationsCompleted() OVERRIDE;
+
+  AppListFolderView* folder_view_;
+  ShowState show_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(FolderBackgroundView);
+};
+
+}  // namespace app_list
+
+#endif  // UI_APP_LIST_VIEWS_FOLDER_BACKGROUND_VIEW_H_