ash: Rename LauncherModel to ShelfModel.

ash/shell/shell_delegate_impl.cc

Index: ash/shell/shell_delegate_impl.cc
diff --git a/ash/shell/shell_delegate_impl.cc b/ash/shell/shell_delegate_impl.cc
index 8e75027a1ab2aed5946a73109d482b8ed7bfbf3f..44d955f67b75637f6e4ec4f13d84db064016dd0e 100644
--- a/ash/shell/shell_delegate_impl.cc
+++ b/ash/shell/shell_delegate_impl.cc
@@ -121,8 +121,7 @@ app_list::AppListViewDelegate* ShellDelegateImpl::CreateAppListViewDelegate() {
   return ash::shell::CreateAppListViewDelegate();
 }
 
-ash::LauncherDelegate* ShellDelegateImpl::CreateLauncherDelegate(
-    ash::LauncherModel* model) {
+LauncherDelegate* ShellDelegateImpl::CreateLauncherDelegate(ShelfModel* model) {
   launcher_delegate_ = new LauncherDelegateImpl(watcher_);
   return launcher_delegate_;
 }