Refactor LauncherItemController and LauncherItemDelegate

ash/launcher/launcher.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/launcher/launcher.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "ash/focus_cycler.h"
@@ skipping 90 matching lines @@
 
 void Launcher::ActivateLauncherItem(int index) {
   // We pass in a keyboard event which will then trigger a switch to the
   // next item if the current one is already active.
   ui::KeyEvent event(ui::ET_KEY_RELEASED,
                      ui::VKEY_UNKNOWN,  // The actual key gets ignored.
                      ui::EF_NONE,
                      false);
 
   const ash::LauncherItem& item = launcher_view_->model()->items()[index];
-  Shell::GetInstance()->launcher_item_delegate_manager()->
-      GetLauncherItemDelegate(item.type)->ItemSelected(item, event);
+  ash::LauncherItemDelegate* item_delegate =
+      Shell::GetInstance()->launcher_item_delegate_manager()->
+          GetLauncherItemDelegate(item.id);
+  if (item_delegate)
+    item_delegate->ItemSelected(event);
 }
 
 void Launcher::CycleWindowLinear(CycleDirection direction) {
   int item_index = GetNextActivatedItemIndex(
       *(launcher_view_->model()), direction);
   if (item_index >= 0)
     ActivateLauncherItem(item_index);
 }
 
 void Launcher::AddIconObserver(LauncherIconObserver* observer) {
@@ skipping 59 matching lines @@
 
 gfx::Rect Launcher::GetLauncherViewBounds() const {
   return launcher_view_->bounds();
 }
 
 app_list::ApplicationDragAndDropHost* Launcher::GetDragAndDropHostForAppList() {
   return launcher_view_;
 }
 
 }  // namespace ash