Support undoing offline page deletion

components/offline_pages/offline_page_model.h

Index: components/offline_pages/offline_page_model.h
diff --git a/components/offline_pages/offline_page_model.h b/components/offline_pages/offline_page_model.h
index 648a0f4002758696ef7cafbc70a3291bf15c0b16..00889892bf830ab50d9032723093e1b8d0b3b715 100644
--- a/components/offline_pages/offline_page_model.h
+++ b/components/offline_pages/offline_page_model.h
@@ -135,6 +135,12 @@ class OfflinePageModel : public KeyedService,
   // will be updated. Requires that the model is loaded.
   void MarkPageAccessed(int64 bookmark_id);
 
+  // Marks that the offline page related to the passed |bookmark_id| was going
+  // to be deleted. The deletion will occur in a short while. The undo can be
+  // done before this. Requires that the model is loaded.
+  void MarkPageForDeletion(int64 bookmark_id,
+                           const DeletePageCallback& callback);
+
   // Deletes an offline page related to the passed |bookmark_id|. Requires that
   // the model is loaded.
   void DeletePageByBookmarkId(int64 bookmark_id,
@@ -145,6 +151,9 @@ class OfflinePageModel : public KeyedService,
   void DeletePagesByBookmarkId(const std::vector<int64>& bookmark_ids,
                                const DeletePageCallback& callback);
 
+  void UndeletePage(int64 bookmark_id,
+                    const DeletePageCallback& callback);
+
   // Gets all available offline pages. Requires that the model is loaded.
   const std::vector<OfflinePageItem> GetAllPages() const;
 
@@ -170,6 +179,9 @@ class OfflinePageModel : public KeyedService,
 
   // BaseBookmarkModelObserver:
   void BookmarkModelChanged() override;
+  void BookmarkNodeAdded(bookmarks::BookmarkModel* model,
+                         const bookmarks::BookmarkNode* parent,
+                         int index) override;
   void BookmarkNodeRemoved(bookmarks::BookmarkModel* model,
                            const bookmarks::BookmarkNode* parent,
                            int old_index,
@@ -208,8 +220,15 @@ class OfflinePageModel : public KeyedService,
   void InformDeletePageDone(const DeletePageCallback& callback,
                             DeletePageResult result);
 
-  void OnUpdateOfflinePageDone(const OfflinePageItem& offline_page_item,
-                               bool success);
+  void OnMarkPageAccesseDone(const OfflinePageItem& offline_page_item,
+                             bool success);
+
+  void OnMarkPageForDeletionDone(const OfflinePageItem& offline_page_item,
+                                 const DeletePageCallback& callback,
+                                 bool success);
+  void OnUndoOfflinePageDone(const OfflinePageItem& offline_page,
+                             bool success);
+  void FinalizePageDeletion();
 
   // Persistent store for offline page metadata.
   scoped_ptr<OfflinePageMetadataStore> store_;