Make shelf item can be dragged when context menu is opened.

ash/shelf/shelf_button.cc

 // Copyright 2013 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/shelf/shelf_button.h"
 
 #include <algorithm>
 
 #include "ash/ash_constants.h"
 #include "ash/shelf/ink_drop_button_listener.h"
@@ skipping 443 matching lines @@
       return;
     case ui::ET_GESTURE_SCROLL_UPDATE:
       shelf_view_->PointerDraggedOnButton(this, ShelfView::TOUCH, *event);
       event->SetHandled();
       return;
     case ui::ET_GESTURE_SCROLL_END:
     case ui::ET_SCROLL_FLING_START:
       shelf_view_->PointerReleasedOnButton(this, ShelfView::TOUCH, false);
       event->SetHandled();
       return;
+    case ui::ET_GESTURE_LONG_TAP:
+      event->SetHandled();

[msw, 2017/06/01 20:24:27]

nit: comment why |event| is ignored (marked handled without any action)?

[minch1, 2017/06/23 23:13:02]

Done.

+      return;
     default:
       return CustomButton::OnGestureEvent(event);
   }
 }
 
 std::unique_ptr<views::InkDropRipple> ShelfButton::CreateInkDropRipple() const {
   return base::MakeUnique<views::SquareInkDropRipple>(
       gfx::Size(kInkDropLargeSize, kInkDropLargeSize),
       kInkDropLargeCornerRadius,
       gfx::Size(kInkDropSmallSize, kInkDropSmallSize),
@@ skipping 31 matching lines @@
   icon_view_->SetHorizontalAlignment(is_horizontal_shelf
                                          ? views::ImageView::CENTER
                                          : views::ImageView::LEADING);
   icon_view_->SetVerticalAlignment(is_horizontal_shelf
                                        ? views::ImageView::LEADING
                                        : views::ImageView::CENTER);
   SchedulePaint();
 }
 
 }  // namespace ash