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..c298aaecfa12bfe948811e3a7e280b5adfc38fb1 100644
--- a/ash/shelf/shelf_view.cc
+++ b/ash/shelf/shelf_view.cc
@@ -642,6 +642,8 @@ 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 +1658,7 @@ void ShelfView::ShowContextMenuForView(views::View* source,
   last_pressed_index_ = -1;
 
   const ShelfItem* item = ShelfItemForView(source);
-  if (!item) {
+  if (!item || item->type == TYPE_APP_LIST) {
     ShellPort::Get()->ShowContextMenu(context_menu_point, source_type);
     return;
   }
@@ -1687,6 +1689,11 @@ void ShelfView::ShowMenu(std::unique_ptr<ui::MenuModel> menu_model,
   if (context_menu)
     run_types |=
         views::MenuRunner::CONTEXT_MENU | views::MenuRunner::FIXED_ANCHOR;
+
+  // Shelf items can only be dragged if the shelf is not autohide.

[msw, 2017/05/17 23:03:30]

nit: s/autohide/in auto-hide/ (or 'is not auto-hidden')

[minch1, 2017/05/26 23:01:11]

update the comment according to next comment.

+  if (wm_shelf()->auto_hide_behavior() == SHELF_AUTO_HIDE_BEHAVIOR_NEVER)

[msw, 2017/05/17 23:03:30]

It's not clear to me how the comment above relates to this code... can you
explain this a bit more?

[minch1, 2017/05/18 17:42:57]

We cannot drag the shelf items when the shelf is auto-hidden (for the SCROLL
events, before open the context menu.) I want to keep the same behavior as
SCROLL events. So, if shelf is auto-hidden, we will not transfer events from
owner to the menu host. Then, shelf items can not be dragged after the context
menu is created.
Set |run_types| here, then, in menu_runner_impl.cc will
|set_owner_needs_gesture_events| according to the |run_types|. Then, in MenuHost
we can know whether we need to transfer events or not.

[msw, 2017/05/18 20:42:20]

Why won't the shelf itself correctly ignore drag touch events when it's in an
auto-hide mode (ie. we shouldn't change the menu's run type based on shelf
state, the shelf itself should handle/ignore gesture events correctly depending
on its internal state). If you need to keep this, add an explanatory comment in
code, like "Shelf items can not be dragged if the shelf is not autohide."

[minch1, 2017/05/26 23:01:11]

Done.

+    run_types |= views::MenuRunner::OWNER_NEEDS_DRAG;
+
   launcher_menu_runner_.reset(
       new views::MenuRunner(menu_model_adapter_->CreateMenu(), run_types));
 
@@ -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)