Unify and change logout/sleep/lock shortcuts

ash/accelerators/accelerator_controller.cc

Index: ash/accelerators/accelerator_controller.cc
diff --git a/ash/accelerators/accelerator_controller.cc b/ash/accelerators/accelerator_controller.cc
index f7a9ecba6754a227faa73cdc8cf3f3154a554106..62e46354db8ba67805793c0f1be12fe70dc9a9aa 100644
--- a/ash/accelerators/accelerator_controller.cc
+++ b/ash/accelerators/accelerator_controller.cc
@@ -574,8 +574,9 @@ bool AcceleratorController::PerformAction(int action,
     case OPEN_FEEDBACK_PAGE:
       ash::Shell::GetInstance()->delegate()->OpenFeedbackPage();
       return true;
-    case EXIT:
-      Shell::GetInstance()->delegate()->Exit();
+    case EXIT_PRESSED:
+    case EXIT_RELEASED:
+      exit_warning_handler_.HandleExitKey(action == EXIT_PRESSED);
       return true;
     case NEW_INCOGNITO_WINDOW:
       Shell::GetInstance()->delegate()->NewWindow(true /* is_incognito */);