Support undoing offline page deletion

components/offline_pages/offline_page_item.h

Index: components/offline_pages/offline_page_item.h
diff --git a/components/offline_pages/offline_page_item.h b/components/offline_pages/offline_page_item.h
index 0ae4a8c21720bd26bd5127b3a0cfefd9e1c3e133..b0c0a8846da0283f1c7b7621a0ff7c437811eae4 100644
--- a/components/offline_pages/offline_page_item.h
+++ b/components/offline_pages/offline_page_item.h
@@ -18,6 +18,12 @@ namespace offline_pages {
 // Metadata of the offline page.
 struct OfflinePageItem {
  public:
+  // Note that this should match with Flags enum in offline_pages.proto.
+  enum Flags {
+    NO_FLAG = 0,
+    MARKED_FOR_DELETION = 0x1,
+  };
+
   OfflinePageItem();
   OfflinePageItem(const GURL& url,
                   int64 bookmark_id,
@@ -33,6 +39,13 @@ struct OfflinePageItem {
   // Gets a URL of the file under |file_path|.
   GURL GetOfflineURL() const;
 
+  // Returns true if the page has been marked for deletion. This allows an undo
+  // in a short time period. After that, the marked page will be deleted.
+  bool IsMarkedForDeletion() const;
+
+  // Clears the mark for deletion.
+  void ClearMarkForDeletion();
+
   // The URL of the page.
   GURL url;
   // The Bookmark ID related to the offline page.
@@ -49,6 +62,8 @@ struct OfflinePageItem {
   base::Time last_access_time;
   // Number of times that the offline archive has been accessed.
   int access_count;
+  // Flags about the state and behavior of the offline page.
+  Flags flags;
 };
 
 }  // namespace offline_pages