Get drag and drop working for win aura.

ash/drag_drop/drag_drop_controller.cc

 // Copyright (c) 2012 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 "ash/drag_drop/drag_drop_controller.h"
 
 #include "ash/drag_drop/drag_drop_tracker.h"
 #include "ash/drag_drop/drag_image_view.h"
 #include "ash/shell.h"
 #include "ash/wm/coordinate_conversion.h"
@@ skipping 88 matching lines @@
 int DragDropController::StartDragAndDrop(
     const ui::OSExchangeData& data,
     aura::RootWindow* root_window,
     aura::Window* source_window,
     const gfx::Point& root_location,
     int operation,
     ui::DragDropTypes::DragEventSource source) {
   if (IsDragDropInProgress())
     return 0;
 
+#if defined(OS_WIN)
+  NOTIMPLEMENTED();
+  return 0;
+#else
+  //  TODO!

[Ben Goodger (Google), 2012/12/07 22:00:26]

let's make this TODO(win_ash) or TODO(cpu)

[jam, 2012/12/07 22:07:29]

Done. Also added comment about two possible approaches to deal with this.

   const ui::OSExchangeDataProviderAura& provider =
       static_cast<const ui::OSExchangeDataProviderAura&>(data.provider());
   // We do not support touch drag/drop without a drag image.
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH &&
       provider.drag_image().size().IsEmpty())
     return 0;
 
   current_drag_event_source_ = source;
   DragDropTracker* tracker = new DragDropTracker(root_window);
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
@@ skipping 54 matching lines @@
 #endif  // !defined(OS_MACOSX)
 
   if (!cancel_animation_.get() || !cancel_animation_->is_animating() ||
       !pending_long_tap_.get()) {
     // If drag cancel animation is running, this cleanup is done when the
     // animation completes.
     if (drag_source_window_)
       drag_source_window_->RemoveObserver(this);
     drag_source_window_ = NULL;
   }
+#endif
 
   return drag_operation_;
 }
 
 void DragDropController::DragUpdate(aura::Window* target,
                                     const ui::LocatedEvent& event) {
   aura::client::DragDropDelegate* delegate = NULL;
   if (target != drag_window_) {
     if (drag_window_) {
       if ((delegate = aura::client::GetDragDropDelegate(drag_window_)))
@@ skipping 297 matching lines @@
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   // Cleanup can be called again while deleting DragDropTracker, so use Pass
   // instead of reset to avoid double free.
   drag_drop_tracker_.Pass();
 }
 
 }  // namespace internal
 }  // namespace ash