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

ash/shelf/shelf_view.cc

Index: ash/shelf/shelf_view.cc
diff --git a/ash/shelf/shelf_view.cc b/ash/shelf/shelf_view.cc
index 5ab343329e7077c3761a20c9b8b526df0e6378c2..afc867f919ddf000a5feb9bb8a93943a65552171 100644
--- a/ash/shelf/shelf_view.cc
+++ b/ash/shelf/shelf_view.cc
@@ -43,6 +43,7 @@
 #include "ui/views/animation/bounds_animator.h"
 #include "ui/views/border.h"
 #include "ui/views/controls/button/image_button.h"
+#include "ui/views/controls/menu/menu_controller.h"
 #include "ui/views/controls/menu/menu_model_adapter.h"
 #include "ui/views/controls/menu/menu_runner.h"
 #include "ui/views/focus/focus_search.h"
@@ -642,6 +643,8 @@ bool ShelfView::ShouldEventActivateButton(View* view, const ui::Event& event) {
 void ShelfView::PointerPressedOnButton(views::View* view,
                                        Pointer pointer,
                                        const ui::LocatedEvent& event) {
+  if (IsShowingMenu())
+    launcher_menu_runner_->Cancel();
   if (drag_view_)
     return;
 
@@ -1656,7 +1659,8 @@ void ShelfView::ShowContextMenuForView(views::View* source,
   last_pressed_index_ = -1;
 
   const ShelfItem* item = ShelfItemForView(source);
-  if (!item) {
+  int index = view_model_->GetIndexOfView(source);
+  if (index == 0 || !item) {

[xiyuan, 2017/05/15 19:20:52]

Why we need to include |index| == 0? Can you document it?

[minch1, 2017/05/15 22:16:34]

This is for the launcher icon (the first item in the shelf). The gesture events
of this item will not go through ShelfButton's OnGestureEvent. This will produce
a flash behavior if long press of the item.
I think it is fine to make the context menu of this item the same as if touching
empty space on the shelf. Since the contents of the context menu in these two
situations are the same.

[xiyuan, 2017/05/15 22:41:10]

It is more accurate to check |item| type than the model index since model index
might change in the future e.g. when UX allows launcher button to float.
i.e. item.type == TYPE_APP_LIST

[minch1, 2017/05/16 22:13:38]

Done.

     ShellPort::Get()->ShowContextMenu(context_menu_point, source_type);
     return;
   }
@@ -1731,6 +1735,9 @@ void ShelfView::ShowMenu(std::unique_ptr<ui::MenuModel> menu_model,
       menu_alignment = views::MENU_ANCHOR_FIXED_SIDECENTER;
   }
 
+  // No dragging if shelf is autohide.
+  if (wm_shelf()->auto_hide_behavior() == SHELF_AUTO_HIDE_BEHAVIOR_NEVER)
+    views::MenuController::SetDoCancel(false);
   // NOTE: if you convert to HAS_MNEMONICS be sure to update menu building code.
   launcher_menu_runner_->RunMenuAt(source->GetWidget(), nullptr, anchor,
                                    menu_alignment, source_type);
@@ -1739,10 +1746,6 @@ void ShelfView::ShowMenu(std::unique_ptr<ui::MenuModel> menu_model,
 void ShelfView::OnMenuClosed(views::InkDrop* ink_drop) {
   context_menu_id_ = ShelfID();
 
-  // Hide the hide overflow bubble after showing a context menu for its items.
-  if (owner_overflow_bubble_)
-    owner_overflow_bubble_->Hide();
-
   closing_event_time_ = launcher_menu_runner_->closing_event_time();
 
   if (ink_drop)