Fix the issue of the dragged item always shown on the primary display.

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_image_view.h"
 #include "ash/shell.h"
+#include "ash/wm/coordinate_conversion.h"
 #include "ash/wm/cursor_manager.h"
 #include "base/message_loop.h"
 #include "base/run_loop.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/drag_drop_delegate.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/base/event.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
@@ skipping 111 matching lines @@
         cursor = ui::kCursorAlias;
       else if (op & ui::DragDropTypes::DRAG_MOVE)
         cursor = ui::kCursorMove;
       drag_cursor_ = cursor;
       ash::Shell::GetInstance()->cursor_manager()->SetCursor(cursor);
     }
   }
 
   DCHECK(drag_image_.get());
   if (drag_image_->visible()) {
+    gfx::Point root_location_in_screen = event.root_location();
+    ash::wm::ConvertPointToScreen(target->GetRootWindow(),
+                                  &root_location_in_screen);
     drag_image_->SetScreenPosition(
-        event.root_location().Subtract(drag_image_offset_));
+        root_location_in_screen.Subtract(drag_image_offset_));
   }
 }
 
 void DragDropController::Drop(aura::Window* target,
                               const ui::LocatedEvent& event) {
   drag_cursor_ = ui::kCursorPointer;
   ash::Shell::GetInstance()->cursor_manager()->SetCursor(ui::kCursorPointer);
   aura::client::DragDropDelegate* delegate = NULL;
 
   // We must guarantee that a target gets a OnDragEntered before Drop. WebKit
@@ skipping 143 matching lines @@
 void DragDropController::Cleanup() {
   if (drag_window_)
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   drag_drop_in_progress_ = false;
 }
 
 }  // namespace internal
 }  // namespace ash