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

ui/views/controls/menu/menu_runner.h

Index: ui/views/controls/menu/menu_runner.h
diff --git a/ui/views/controls/menu/menu_runner.h b/ui/views/controls/menu/menu_runner.h
index abba98e9dd4095862b385ff57b26a6b49f3e2789..2a0b9b5704ff5751c535658dfeb5417a37f77832 100644
--- a/ui/views/controls/menu/menu_runner.h
+++ b/ui/views/controls/menu/menu_runner.h
@@ -89,6 +89,12 @@ class VIEWS_EXPORT MenuRunner {
     // Menu with fixed anchor position, so |MenuRunner| will not attempt to
     // adjust the anchor point. For example the context menu of shelf item.
     FIXED_ANCHOR = 1 << 6,
+
+#if !defined(OS_MACOSX)
+    // Owner of the menu can be dragged after menu is created. For example the

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

This is weird to me, I'd like to see it in action. Does dragging close the menu?

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

Yes, dragging will close the menu.

+    // shelf item can be dragged when the context menu of the item is opened.
+    OWNER_NEEDS_DRAG = 1 << 7,

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

nit: SEND_UNHANDLED_GESTURES_TO_OWNER or similar?

[minch1, 2017/05/26 23:01:15]

Done.

+#endif
   };
 
   // Creates a new MenuRunner, which may use a native menu if available.