Store AppItems as pages in AppListModel.

ui/app_list/app_list_item_model.h

Index: ui/app_list/app_list_item_model.h
diff --git a/ui/app_list/app_list_item_model.h b/ui/app_list/app_list_item_model.h
index 859b348fe98f2a0f5a7774d5b0ee7d66654b9a28..0ad9e93ca0e5c2dc75629354c9e86dd81c081580 100644
--- a/ui/app_list/app_list_item_model.h
+++ b/ui/app_list/app_list_item_model.h
@@ -9,6 +9,7 @@
 
 #include "base/basictypes.h"
 #include "base/observer_list.h"
+#include "sync/api/string_ordinal.h"
 #include "ui/app_list/app_list_export.h"
 #include "ui/gfx/image/image_skia.h"
 
@@ -46,6 +47,10 @@ class APP_LIST_EXPORT AppListItemModel {
   int percent_downloaded() const { return percent_downloaded_; }
 
   const std::string& id() const { return id_; }
+  const syncer::StringOrdinal& position() const { return position_; }
+  void set_position(syncer::StringOrdinal& new_position) {
+    position_ = new_position;
+  }
 
   void AddObserver(AppListItemModelObserver* observer);
   void RemoveObserver(AppListItemModelObserver* observer);
@@ -68,6 +73,7 @@ class APP_LIST_EXPORT AppListItemModel {
 
  private:
   const std::string id_;
+  syncer::StringOrdinal position_;
   gfx::ImageSkia icon_;
   bool has_shadow_;
   std::string title_;