Split out Ash dependency in app info dialog unittests

chrome/browser/ui/views/apps/app_info_dialog/app_info_footer_panel.cc

Index: chrome/browser/ui/views/apps/app_info_dialog/app_info_footer_panel.cc
diff --git a/chrome/browser/ui/views/apps/app_info_dialog/app_info_footer_panel.cc b/chrome/browser/ui/views/apps/app_info_dialog/app_info_footer_panel.cc
index f8851b86508556a24e275237d2797d5666d37818..45c34cb4841f022d5f3d04a814b73c2537f84ada 100644
--- a/chrome/browser/ui/views/apps/app_info_dialog/app_info_footer_panel.cc
+++ b/chrome/browser/ui/views/apps/app_info_dialog/app_info_footer_panel.cc
@@ -170,8 +170,9 @@ void AppInfoFooterPanel::SetPinnedToShelf(bool value) {
 bool AppInfoFooterPanel::CanSetPinnedToShelf() const {
 #if defined(USE_ASH)
   // Non-Ash platforms don't have a shelf.
-  if (chrome::GetHostDesktopTypeForNativeWindow(parent_window_) !=
-      chrome::HOST_DESKTOP_TYPE_ASH) {
+  if (!ash::Shell::HasInstance() ||
+      chrome::GetHostDesktopTypeForNativeWindow(parent_window_) !=
+          chrome::HOST_DESKTOP_TYPE_ASH) {
     return false;
   }