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..0229ed86997767b2fbb8b7e630e9ce1fd2627156 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_CHROMEOS)
+    // Menu that can be dragged when menu is opened. For example the shelf
+    // item can be dragged when the context menu of the item is opened.
+    IS_DRAGGABLE = 1 << 7,

[xiyuan, 2017/05/16 22:46:57]

IS_DRAGGABLE is confusing. On first read, I thought it means the menu item is
draggable. How about call it OWNER_NEEDS_DRAG or something similar ?

[minch1, 2017/05/17 16:55:38]

Done.

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