Moves app_list() and related functions from Shell to WmShell

ash/app_list/app_list_delegate_impl.cc

Index: ash/app_list/app_list_delegate_impl.cc
diff --git a/ash/app_list/app_list_delegate_impl.cc b/ash/app_list/app_list_delegate_impl.cc
index 8f5c63b963670a0f31aecb8796317efd0d46d348..4013786bbeaeba1b9dbdbc039312c537e5c3f577 100644
--- a/ash/app_list/app_list_delegate_impl.cc
+++ b/ash/app_list/app_list_delegate_impl.cc
@@ -9,16 +9,17 @@
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/wm_shell.h"
 #include "ash/root_window_controller.h"
+#include "ash/shell.h"
 #include "ui/app_list/presenter/app_list.h"
 
 namespace ash {
 
 AppListDelegateImpl::AppListDelegateImpl() {
-  WmShell::Get()->app_list()->set_delegate(this);
+  Shell::Get()->app_list()->set_delegate(this);
 }
 
 AppListDelegateImpl::~AppListDelegateImpl() {
-  WmShell::Get()->app_list()->set_delegate(nullptr);
+  Shell::Get()->app_list()->set_delegate(nullptr);
 }
 
 void AppListDelegateImpl::OnAppListVisibilityChanged(bool visible,