[Merge M60] Fix shelf dragging context in case Context Menu is shown.

ash/shelf/shelf_view.h

 // 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.
 
 #ifndef ASH_SHELF_SHELF_VIEW_H_
 #define ASH_SHELF_SHELF_VIEW_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 151 matching lines @@
 
   // Return the view model for test purposes.
   const views::ViewModel* view_model_for_test() const {
     return view_model_.get();
   }
 
   // Return the main shelf. This will return nullptr if this is not called on
   // the overflow shelf.
   ShelfView* main_shelf() { return main_shelf_; }
 
+  const ShelfButton* drag_view() const { return drag_view_; }
+
  private:
   friend class ash::test::ShelfViewTestAPI;
 
   class FadeOutAnimationDelegate;
   class StartFadeAnimationDelegate;
 
   enum RemovableState {
     REMOVABLE,      // Item can be removed when dragged away.
     DRAGGABLE,      // Item can be dragged, but will snap always back to origin.
     NOT_REMOVABLE,  // Item is fixed and can never be removed.
@@ skipping 291 matching lines @@
   ShelfButtonPressedMetricTracker shelf_button_pressed_metric_tracker_;
 
   base::WeakPtrFactory<ShelfView> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_VIEW_H_