Add a skeleton Start Page to the experimental app list.

ui/app_list/views/contents_view.h

Index: ui/app_list/views/contents_view.h
diff --git a/ui/app_list/views/contents_view.h b/ui/app_list/views/contents_view.h
index eb2ec6def49adf394a4e3b631d4014cc05660ad2..56b5e330fd62269fe557b73c0f4117cb4de47be7 100644
--- a/ui/app_list/views/contents_view.h
+++ b/ui/app_list/views/contents_view.h
@@ -29,6 +29,7 @@ class AppListModel;
 class AppListViewDelegate;
 class AppsContainerView;
 class PaginationModel;
+class StartPageView;
 
 // A view to manage sub views under the search box (apps grid view + page
 // switcher and search results). The two sets of sub views are mutually
@@ -36,7 +37,11 @@ class PaginationModel;
 // and animates the transition between show states.
 class ContentsView : public views::View {
  public:
-  enum ShowState { SHOW_APPS, SHOW_SEARCH_RESULTS, };
+  enum ShowState {
+    SHOW_APPS,
+    SHOW_SEARCH_RESULTS,
+    SHOW_START_PAGE,
+  };
 
   ContentsView(AppListMainView* app_list_main_view,
                PaginationModel* pagination_model,
@@ -83,6 +88,7 @@ class ContentsView : public views::View {
   PaginationModel* pagination_model_;  // Owned by AppListController.
 
   AppsContainerView* apps_container_view_;  // Owned by the views hierarchy.
+  AppListMainView* app_list_main_view_;     // Owned by the views hierarchy.
 
   scoped_ptr<views::ViewModel> view_model_;
   scoped_ptr<views::BoundsAnimator> bounds_animator_;