Don't activate a window if screen is locked.

ui/aura/window.h

Index: ui/aura/window.h
diff --git a/ui/aura/window.h b/ui/aura/window.h
index a97194c0b7a3869b099aa7a318001fae67cb82b3..fd799c97f2dee96e3795396cc30be853aa2c129d 100644
--- a/ui/aura/window.h
+++ b/ui/aura/window.h
@@ -178,13 +178,18 @@ class AURA_EXPORT Window : public ui::LayerDelegate {
   void RemoveObserver(WindowObserver* observer);
 
   // When set to true, this Window will stop propagation of all events targeted
-  // at Windows below it in the z-order, but only if this Window has children.
+  // at Windows below it in the z-order, but only if this Window has children
+  // with the stops_event_propagation_ is true. If none of child has this
+  // property as true, then event will not be stopped.
   // This is used to implement lock-screen type functionality where we do not
   // want events to be sent to running logged-in windows when the lock screen is
   // displayed.
   void set_stops_event_propagation(bool stops_event_propagation) {
     stops_event_propagation_ = stops_event_propagation;
   }
+  bool stops_event_propagation() const {
+    return stops_event_propagation_;
+  }
 
   void set_ignore_events(bool ignore_events) { ignore_events_ = ignore_events; }
 
@@ -220,6 +225,9 @@ class AURA_EXPORT Window : public ui::LayerDelegate {
   // Returns true if the Window can be focused.
   virtual bool CanFocus() const;
 
+  // Returns true if the Window can receive events.
+  virtual bool CanReceiveEvents() const;
+
   // Returns the FocusManager for the Window, which may be attached to a parent
   // Window. Can return NULL if the Window has no FocusManager.
   virtual internal::FocusManager* GetFocusManager();
@@ -250,6 +258,10 @@ class AURA_EXPORT Window : public ui::LayerDelegate {
   void* GetProperty(const char* name) const;
   int GetIntProperty(const char* name) const;
 
+  // This window is currently stopping event propagation for any windows behind
+  // it in the z-order.
+  bool StopsEventPropagation() const;
+
  protected:
   // Returns the root window or NULL if we aren't yet attached to the root
   // window.
@@ -272,10 +284,6 @@ class AURA_EXPORT Window : public ui::LayerDelegate {
   // Schedules a paint for the Window's entire bounds.
   void SchedulePaint();
 
-  // This window is currently stopping event propagation for any windows behind
-  // it in the z-order.
-  bool StopsEventPropagation() const;
-
   // Gets a Window (either this one or a subwindow) containing |local_point|.
   // If |return_tightest| is true, returns the tightest-containing (i.e.
   // furthest down the hierarchy) Window containing the point; otherwise,
@@ -298,6 +306,9 @@ class AURA_EXPORT Window : public ui::LayerDelegate {
   // Updates the layer name with a name based on the window's name and id.
   void UpdateLayerName(const std::string& name);
 
+  // Returns true if the Window is behind a window that stops event propagation.
+  bool IsBehindStopEventsWindow() const;
+
   client::WindowType type_;
 
   WindowDelegate* delegate_;