mus: Unset the cursor client during teardown.

ui/views/mus/desktop_window_tree_host_mus.cc

Index: ui/views/mus/desktop_window_tree_host_mus.cc
diff --git a/ui/views/mus/desktop_window_tree_host_mus.cc b/ui/views/mus/desktop_window_tree_host_mus.cc
index c3097bd499666b4fe677a99dc499a001b7568652..cf437bcf95b4ae068ac92fee7bd9a74a16bc8984 100644
--- a/ui/views/mus/desktop_window_tree_host_mus.cc
+++ b/ui/views/mus/desktop_window_tree_host_mus.cc
@@ -193,6 +193,10 @@ DesktopWindowTreeHostMus::~DesktopWindowTreeHostMus() {
   MusClient::Get()->RemoveObserver(this);
   aura::Env::GetInstance()->RemoveObserver(this);
   desktop_native_widget_aura_->OnDesktopWindowTreeHostDestroyed(this);
+  // The cursor-client can be accessed during WindowTreeHostMus tear-down. So
+  // the cursor client needs to be unset on the root-window before
+  // |cursor_manager_| is destroyed.
+  aura::client::SetCursorClient(window(), nullptr);

[James Cook, 2016/12/21 04:02:31]

nit: Should this be done before line 193 so that things are torn down in the
opposite order to their initialization?

[sadrul, 2016/12/21 17:45:57]

Done.

 }
 
 bool DesktopWindowTreeHostMus::IsDocked() const {