linux aura: Show the drag-image when available.

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.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 "ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.h"
 
 #include <X11/Xatom.h>
 
 #include "base/event_types.h"
 #include "base/lazy_instance.h"
@@ skipping 569 matching lines @@
       provider);
 
   source_provider_->TakeOwnershipOfSelection();
 
   std::vector< ::Atom> actions = GetOfferedDragOperations();
   ui::SetAtomArrayProperty(xwindow_, "XdndActionList", "ATOM", actions);
 
   // Windows has a specific method, DoDragDrop(), which performs the entire
   // drag. We have to emulate this, so we spin off a nested runloop which will
   // track all cursor movement and reroute events to a specific handler.
+  move_loop_.SetDragImage(source_provider_->GetDragImage(),
+                          source_provider_->GetDragImageOffset());
   move_loop_.RunMoveLoop(source_window, grab_cursor_);
+  move_loop_.SetDragImage(gfx::ImageSkia(), gfx::Vector2dF());
 
   source_provider_ = NULL;
   drag_drop_in_progress_ = false;
   drag_operation_ = 0;
   XDeleteProperty(xdisplay_, xwindow_, atom_cache_.GetAtom("XdndActionList"));
 
   return resulting_operation_;
 }
 
 void DesktopDragDropClientAuraX11::DragUpdate(aura::Window* target,
@@ skipping 317 matching lines @@
   // GdkEvent about the failed drag. (And sending this message doesn't appear
   // to go through normal xlib machinery, but instead passes through the low
   // level xProto (the x11 wire format) that I don't understand.
   //
   // I'm unsure if I have to jump through those hoops, or if XSendEvent is
   // sufficient.
   XSendEvent(xdisplay_, xid, False, 0, xev);
 }
 
 }  // namespace views