First shot at implementing drag&drop for Aura

ui/aura_shell/shell.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_SHELL_SHELL_H_
 #define UI_AURA_SHELL_SHELL_H_
 #pragma once
 
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/task.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "ui/aura/desktop_delegate.h"
+#include "ui/aura/drag_drop_controller.h"
 #include "ui/aura_shell/aura_shell_export.h"
 
 namespace aura {
+class MouseEvent;
 class Window;
 }
 namespace gfx {
+class Point;
 class Rect;
 }
 
+namespace ui {
+class OSExchangeData;
+}
+
+namespace views {
+class Widget;
+}
+
 namespace aura_shell {
 
 class Launcher;
 class ShellDelegate;
 
 namespace internal {
 class WorkspaceController;
 }
 
 // Shell is a singleton object that presents the Shell API and implements the
 // Desktop's delegate interface.
-class AURA_SHELL_EXPORT Shell : public aura::DesktopDelegate {
+class AURA_SHELL_EXPORT Shell : public aura::DesktopDelegate,
+                                public aura::DragDropController {
  public:
   // Upon creation, the Shell sets itself as the Desktop's delegate, which takes
   // ownership of the Shell.
   Shell();
   virtual ~Shell();
 
   static Shell* GetInstance();
 
   void Init();
 
@@ skipping 12 matching lines @@
  private:
   typedef std::pair<aura::Window*, gfx::Rect> WindowAndBoundsPair;
 
   // Enables WorkspaceManager.
   void EnableWorkspaceManager();
 
   // Overridden from aura::DesktopDelegate:
   virtual void AddChildToDefaultParent(aura::Window* window) OVERRIDE;
   virtual aura::Window* GetTopmostWindowToActivate(
       aura::Window* ignore) const OVERRIDE;
+  virtual DragDropController* GetDragDropController() const OVERRIDE;
+
+  // Overridden from aura::DragDropController:
+  virtual void StartDragAndDrop(const ui::OSExchangeData& data,
+                                int operation,
+                                const gfx::Point& location) OVERRIDE;
+  virtual void DragUpdate(const aura::MouseEvent& event) OVERRIDE;
+  virtual void Drop(const aura::MouseEvent& event) OVERRIDE;
 
   static Shell* instance_;
 
   std::vector<WindowAndBoundsPair> to_restore_;
 
   base::WeakPtrFactory<Shell> method_factory_;
 
   scoped_ptr<ShellDelegate> delegate_;
 
   scoped_ptr<Launcher> launcher_;
 
   scoped_ptr<internal::WorkspaceController> workspace_controller_;
 
+  const ui::OSExchangeData* drag_data_;
+  scoped_ptr<views::Widget> drag_widget_;
+
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace aura_shell
 
 #endif  // UI_AURA_SHELL_SHELL_H_