Prevents crash when a menu gets closed during drag

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

Index: ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
index 8341bce675d29b5de1eff717030e4c6da89d45f6..677f3db8b4c1e3d2007273bc364d11051e6b2c5c 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
@@ -490,8 +490,7 @@ void DesktopNativeWidgetAura::InitNativeWidget(
 
   window_tree_client_.reset(
       new DesktopNativeWidgetAuraWindowTreeClient(host_->window()));
-  drop_helper_.reset(new DropHelper(
-      static_cast<internal::RootView*>(GetWidget()->GetRootView())));
+  drop_helper_.reset(new DropHelper(GetWidget()->GetRootView()));
   aura::client::SetDragDropDelegate(content_window_, this);
 
   tooltip_manager_.reset(new TooltipManagerAura(GetWidget()));
@@ -591,6 +590,8 @@ void DesktopNativeWidgetAura::ReorderNativeViews() {
 }
 
 void DesktopNativeWidgetAura::ViewRemoved(View* view) {
+  DCHECK(drop_helper_.get() != NULL);
+  drop_helper_->ResetTargetViewIfEquals(view);

[varkha, 2014/03/31 17:40:52]

This is same as the code in NativeWidgetAura::ViewRemoved and is here for the
same reason.
https://code.google.com/p/chromium/codesearch#chromium/src/ui/views/widget/na...

 }
 
 void DesktopNativeWidgetAura::SetNativeWindowProperty(const char* name,