Fix remaining incompatibilities between scoped_ptr and unique_ptr.

ash/wm/window_state.h

Index: ash/wm/window_state.h
diff --git a/ash/wm/window_state.h b/ash/wm/window_state.h
index c17dc0deb1408089ff232a0a2238b8251374a638..8bf338e5efe30ebfb57ef4b2ede13dbc142659e3 100644
--- a/ash/wm/window_state.h
+++ b/ash/wm/window_state.h
@@ -231,9 +231,7 @@ class ASH_EXPORT WindowState : public aura::WindowObserver {
   void RemoveObserver(WindowStateObserver* observer);
 
   // Whether the window is being dragged.
-  bool is_dragged() const {
-    return drag_details_;
-  }
+  bool is_dragged() const { return !!drag_details_; }
 
   // Whether or not the window's position can be managed by the
   // auto management logic.