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

ui/views/controls/menu/menu_controller.cc

Index: ui/views/controls/menu/menu_controller.cc
diff --git a/ui/views/controls/menu/menu_controller.cc b/ui/views/controls/menu/menu_controller.cc
index a5ecb7df05c4a3fc1bda4e00ee870b38a24475e9..bb9ed0e1550a2a584223839d91a653ac7850f825 100644
--- a/ui/views/controls/menu/menu_controller.cc
+++ b/ui/views/controls/menu/menu_controller.cc
@@ -401,6 +401,7 @@ MenuController::State::~State() {}
 
 // static
 MenuController* MenuController::active_instance_ = NULL;
+bool MenuController::do_cancel_ = true;
 
 // static
 MenuController* MenuController::GetActiveInstance() {
@@ -820,9 +821,16 @@ void MenuController::OnGestureEvent(SubmenuView* source,
   if (event->stopped_propagation())
       return;
 
-  if (!part.submenu)
+  if (part.submenu) {
+    part.submenu->OnGestureEvent(event);
     return;
-  part.submenu->OnGestureEvent(event);
+  }
+
+  if (!DoCancel()) {
+    event->ConvertLocationToTarget(source->GetWidget()->GetNativeWindow(),
+                                   owner()->GetNativeWindow());
+    owner()->OnGestureEvent(event);
+  }
 }
 
 void MenuController::OnTouchEvent(SubmenuView* source, ui::TouchEvent* event) {