Cleanup shelf initialization and observation.

ash/shelf/shelf_widget.cc

 // Copyright 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/shelf/shelf_widget.h"
 
 #include "ash/ash_switches.h"
 #include "ash/focus_cycler.h"
 #include "ash/root_window_controller.h"
 #include "ash/session/session_state_delegate.h"
@@ skipping 704 matching lines @@
     case user::LOGGED_IN_OWNER:
       return true;
     case user::LOGGED_IN_PUBLIC:
     case user::LOGGED_IN_SUPERVISED:
     case user::LOGGED_IN_GUEST:
     case user::LOGGED_IN_KIOSK_APP:
     case user::LOGGED_IN_NONE:
       return false;
   }
 
-  DCHECK(false);
+  NOTREACHED();
   return false;
 }
 
 ShelfAlignment ShelfWidget::GetAlignment() const {
-  return shelf_layout_manager_->GetAlignment();
+  // TODO(msw): This should not be called before |shelf_| is created.
+  return shelf_ ? shelf_->GetAlignment() : SHELF_ALIGNMENT_BOTTOM;
 }
 
-void ShelfWidget::SetAlignment(ShelfAlignment alignment) {
-  if (shelf_)
-    shelf_->SetAlignment(alignment);
-  status_area_widget_->SetShelfAlignment(alignment);
+void ShelfWidget::OnShelfAlignmentChanged() {
+  status_area_widget_->SetShelfAlignment(GetAlignment());
   delegate_view_->SchedulePaint();
 }
 
 void ShelfWidget::SetDimsShelf(bool dimming) {
   delegate_view_->SetDimmed(dimming);
   // Repaint all children, allowing updates to reflect dimmed state eg:
   // status area background, app list button and overflow button.
   if (shelf_)
     shelf_->SchedulePaint();
   status_area_widget_->SchedulePaint();
 }
 
 bool ShelfWidget::GetDimsShelf() const {
   return delegate_view_->GetDimmed();
 }
 
 void ShelfWidget::CreateShelf() {
   if (shelf_)
     return;
 
   Shell* shell = Shell::GetInstance();
-  // This needs to be called before shelf_model().
-  ShelfDelegate* shelf_delegate = shell->GetShelfDelegate();
-  if (!shelf_delegate)
-    return;  // Not ready to create Shelf.
+  ShelfDelegate* delegate = shell->GetShelfDelegate();
+  shelf_.reset(new Shelf(shell->shelf_model(), delegate, this));
+  delegate->OnShelfCreated(shelf_.get());
 
-  shelf_.reset(
-      new Shelf(shell->shelf_model(), shell->GetShelfDelegate(), this));
   SetFocusCycler(shell->focus_cycler());
 
   // Inform the root window controller.
   RootWindowController::ForWindow(window_container_)->OnShelfCreated();
 
   shelf_->SetVisible(
       shell->session_state_delegate()->IsActiveUserSessionStarted());
   shelf_layout_manager_->LayoutShelf();
   shelf_layout_manager_->UpdateAutoHideState();
   Show();
@@ skipping 55 matching lines @@
   DCHECK(delegate_view_);
   return delegate_view_->disable_dimming_animations_for_test();
 }
 
 void ShelfWidget::WillDeleteShelf() {
   shelf_layout_manager_->RemoveObserver(this);
   shelf_layout_manager_ = NULL;
 }
 
 }  // namespace ash