Don't activate a window if screen is locked.

ash/wm/activation_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/wm/activation_controller.h"
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/window_modality_controller.h"
 #include "ash/wm/window_util.h"
@@ skipping 101 matching lines @@
   if (!window)
     return;
   // Nothing may actually have changed.
   aura::Window* old_active = GetActiveWindow();
   if (old_active == window)
     return;
   // The stacking client may impose rules on what window configurations can be
   // activated or deactivated.
   if (!CanActivateWindow(window))
     return;
+  // If the screen is locked, just bring the window to top so that
+  // it will be activated when the lock window is destroyed.
+  if (window && !window->CanReceiveEvents()) {
+    StackTransientParentsBelowModalWindow(window);
+    window->parent()->StackChildAtTop(window);
+    return;
+  }
 
   if (!window->Contains(window->GetFocusManager()->GetFocusedWindow()))
     window->GetFocusManager()->SetFocusedWindow(window);
   aura::RootWindow::GetInstance()->SetProperty(
       aura::client::kRootWindowActiveWindow,
       window);
   // Invoke OnLostActive after we've changed the active window. That way if the
   // delegate queries for active state it doesn't think the window is still
   // active.
   if (old_active && aura::client::GetActivationDelegate(old_active))
     aura::client::GetActivationDelegate(old_active)->OnLostActive();
+
   if (window) {
     StackTransientParentsBelowModalWindow(window);
     window->parent()->StackChildAtTop(window);
     if (aura::client::GetActivationDelegate(window))
       aura::client::GetActivationDelegate(window)->OnActivated();
   }
 }
 
 void ActivationController::DeactivateWindow(aura::Window* window) {
   if (window)
@@ skipping 61 matching lines @@
        i != container->children().rend();
        ++i) {
     if (*i != ignore && CanActivateWindow(*i))
       return *i;
   }
   return NULL;
 }
 
 }  // namespace internal
 }  // namespace ash