First shot at implementing drag&drop for Aura

ui/aura_shell/shell.cc

 // 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.
 
 #include "ui/aura_shell/shell.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "ui/aura/aura_switches.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/drag_drop_client.h"
 #include "ui/aura/desktop.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_types.h"
 #include "ui/aura_shell/default_container_event_filter.h"
 #include "ui/aura_shell/default_container_layout_manager.h"
 #include "ui/aura_shell/desktop_event_filter.h"
 #include "ui/aura_shell/desktop_layout_manager.h"
+#include "ui/aura_shell/drag_drop_controller.h"
 #include "ui/aura_shell/launcher/launcher.h"
 #include "ui/aura_shell/shelf_layout_controller.h"
 #include "ui/aura_shell/shell_delegate.h"
 #include "ui/aura_shell/shell_factory.h"
 #include "ui/aura_shell/shell_window_ids.h"
 #include "ui/aura_shell/stacking_controller.h"
 #include "ui/aura_shell/toplevel_layout_manager.h"
 #include "ui/aura_shell/toplevel_window_event_filter.h"
 #include "ui/aura_shell/workspace_controller.h"
 #include "ui/gfx/compositor/layer.h"
@@ skipping 55 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // Shell, public:
 
 Shell::Shell(ShellDelegate* delegate)
     : ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)),
       delegate_(delegate) {
   aura::Desktop::GetInstance()->SetEventFilter(
       new internal::DesktopEventFilter);
   aura::Desktop::GetInstance()->SetStackingClient(
       new internal::StackingController);
+  aura::Desktop::GetInstance()->SetProperty(aura::kDesktopDragDropClientKey,
+      static_cast<aura::DragDropClient*>(new internal::DragDropController));
 }
 
 Shell::~Shell() {
   DCHECK(instance_ == this);
   instance_ = NULL;
 
   // Make sure we delete WorkspaceController before launcher is
   // deleted as it has a reference to launcher model.
   workspace_controller_.reset();
 }
@@ skipping 94 matching lines @@
       new internal::WorkspaceController(default_container));
   workspace_controller_->SetLauncherModel(launcher_->model());
   default_container->SetEventFilter(
       new internal::DefaultContainerEventFilter(default_container));
   default_container->SetLayoutManager(
       new internal::DefaultContainerLayoutManager(
           workspace_controller_->workspace_manager()));
 }
 
 }  // namespace aura_shell