ash: Fix event processing in modal windows in login/lock screen.

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 95b6f9d1fc074465b9c90c76805d54667cd16d1d..ec062d02be661fbfc92bd1968565423984ad6f1f 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -233,6 +233,7 @@ Shell::~Shell() {
 
   // The status area needs to be shut down before the windows are destroyed.
   status_area_widget_->Shutdown();
+  status_area_widget_ = NULL;
 
   // AppList needs to be released before shelf layout manager, which is
   // destroyed with launcher container in the loop below. However, app list
@@ -671,7 +672,7 @@ void Shell::CreateModalBackground() {
   RootWindowControllerList controllers = GetAllRootWindowControllers();
   for (RootWindowControllerList::iterator iter = controllers.begin();
        iter != controllers.end(); ++iter)
-    (*iter)->GetSystemModalLayoutManager()->CreateModalBackground();
+    (*iter)->GetSystemModalLayoutManager(NULL)->CreateModalBackground();
 }
 
 void Shell::OnModalWindowRemoved(aura::Window* removed) {
@@ -679,24 +680,26 @@ void Shell::OnModalWindowRemoved(aura::Window* removed) {
   bool activated = false;
   for (RootWindowControllerList::iterator iter = controllers.begin();
        iter != controllers.end() && !activated; ++iter) {
-    activated =
-        (*iter)->GetSystemModalLayoutManager()->ActivateNextModalWindow();
+    activated = (*iter)->GetSystemModalLayoutManager(removed)->
+        ActivateNextModalWindow();
   }
   if (!activated) {
     RemoveEnvEventFilter(modality_filter_.get());
     modality_filter_.reset();
     for (RootWindowControllerList::iterator iter = controllers.begin();
          iter != controllers.end(); ++iter)
-      (*iter)->GetSystemModalLayoutManager()->DestroyModalBackground();
+      (*iter)->GetSystemModalLayoutManager(removed)->DestroyModalBackground();
   }
 }
 
 SystemTrayDelegate* Shell::tray_delegate() {
-  return status_area_widget_->system_tray_delegate();
+  return status_area_widget_ ? status_area_widget_->system_tray_delegate() :
+                               NULL;
 }
 
 SystemTray* Shell::system_tray() {
-  return status_area_widget_->system_tray();
+  return status_area_widget_ ? status_area_widget_->system_tray() :
+                               NULL;
 }
 
 void Shell::InitRootWindowForSecondaryDisplay(aura::RootWindow* root) {
@@ -758,9 +761,9 @@ void Shell::InitRootWindowController(
       root_window->GetChildById(internal::kShellWindowId_AlwaysOnTopContainer));
   root_window->SetProperty(internal::kAlwaysOnTopControllerKey,
                            always_on_top_controller);
-  if (GetPrimaryRootWindowController()->GetSystemModalLayoutManager()->
+  if (GetPrimaryRootWindowController()->GetSystemModalLayoutManager(NULL)->
           has_modal_background()) {
-    controller->GetSystemModalLayoutManager()->CreateModalBackground();
+    controller->GetSystemModalLayoutManager(NULL)->CreateModalBackground();
   }
 
   window_cycle_controller_->OnRootWindowAdded(root_window);
@@ -820,7 +823,7 @@ bool Shell::CanWindowReceiveEvents(aura::Window* window) {
   RootWindowControllerList controllers = GetAllRootWindowControllers();
   for (RootWindowControllerList::iterator iter = controllers.begin();
        iter != controllers.end(); ++iter) {
-    if ((*iter)->GetSystemModalLayoutManager()->
+    if ((*iter)->GetSystemModalLayoutManager(window)->
             CanWindowReceiveEvents(window)) {
       return true;
     }