First shot at implementing drag&drop for Aura

ui/aura/window.h

 // Copyright (c) 2011 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_AURA_WINDOW_H_
 #define UI_AURA_WINDOW_H_
 #pragma once
 
 #include <map>
 #include <vector>
@@ skipping 24 matching lines @@
 namespace aura {
 
 class Desktop;
 class EventFilter;
 class KeyEvent;
 class LayoutManager;
 class MouseEvent;
 class ToplevelWindowContainer;
 class TouchEvent;
 class WindowDelegate;
+class WindowDragDropDelegate;
 class WindowObserver;
 
 namespace internal {
 class FocusManager;
 }
 
 // Aura window implementation. Interesting events are sent to the
 // WindowDelegate.
 // TODO(beng): resolve ownership.
 class AURA_EXPORT Window : public ui::LayerDelegate {
@@ skipping 28 matching lines @@
   const gfx::Rect& bounds() const;
   const gfx::Rect& restore_bounds() const { return restore_bounds_; }
 
   Window* parent() { return parent_; }
   const Window* parent() const { return parent_; }
 
   // The Window does not own this object.
   void set_user_data(void* user_data) { user_data_ = user_data; }
   void* user_data() const { return user_data_; }
 
+  WindowDragDropDelegate* drag_drop_delegate() { return drag_drop_delegate_; }
+  void set_drag_drop_delegate(WindowDragDropDelegate* drag_drop_delegate) {
+    drag_drop_delegate_ = drag_drop_delegate;
+  }
+
   // Changes the visibility of the window.
   void Show();
   void Hide();
   // Returns true if this window and all its ancestors are visible.
   bool IsVisible() const;
 
   // Returns the window's bounds in screen coordinates.
   gfx::Rect GetScreenBounds() const;
 
   // Activates this window. Only top level windows can be activated. Requests
@@ skipping 239 matching lines @@
 
   ObserverList<WindowObserver> observers_;
 
   // We're using ViewProp to store the property (for now) instead of
   // just using std::map because chrome is still using |ViewProp| class
   // to create and access property.
   // TODO(oshima): Consolidcate ViewProp and aura::window property
   // implementation.
   std::map<const char*, void*> prop_map_;
 
+  // Delegate for handling drag and drop operations.
+  WindowDragDropDelegate* drag_drop_delegate_;

[Ben Goodger (Google), 2011/11/11 17:26:53]

I think we should not add this directly to Window. Instead, this can be a
property that gets set. See client/aura_constants.h

[varunjain, 2011/11/15 19:39:33]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(Window);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_H_