More work to make ash_unittests pass when we require context.

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 134 matching lines @@
   int drag_image_vertical_offset = 0;
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
     drag_image_scale = kTouchDragImageScale;
     drag_image_vertical_offset = kTouchDragImageVerticalOffset;
   }
   gfx::Point start_location = root_location;
   ash::wm::ConvertPointToScreen(root_window, &start_location);
   drag_image_final_bounds_for_cancel_animation_ = gfx::Rect(
       start_location - provider->GetDragImageOffset(),
       provider->GetDragImage().size());
-  drag_image_.reset(new DragImageView);
+  drag_image_.reset(new DragImageView(source_window->GetRootWindow()));
   drag_image_->SetImage(provider->GetDragImage());
   drag_image_offset_ = provider->GetDragImageOffset();
   gfx::Rect drag_image_bounds(start_location, drag_image_->GetPreferredSize());
   drag_image_bounds = AdjustDragImageBoundsForScaleAndOffset(drag_image_bounds,
       drag_image_vertical_offset, drag_image_scale, &drag_image_offset_);
   drag_image_->SetBoundsInScreen(drag_image_bounds);
   drag_image_->SetWidgetVisible(true);
 
   drag_window_ = NULL;
 
@@ skipping 329 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