Supporting undoing bookmark deletion without creating new ID.

components/bookmarks/browser/bookmark_model.h

Index: components/bookmarks/browser/bookmark_model.h
diff --git a/components/bookmarks/browser/bookmark_model.h b/components/bookmarks/browser/bookmark_model.h
index 27837703d0adc6719ef330fb483cd6afe1d1bcb7..6f1a57a7c60848905b40e3e2256a8ca6dd08a524 100644
--- a/components/bookmarks/browser/bookmark_model.h
+++ b/components/bookmarks/browser/bookmark_model.h
@@ -68,6 +68,20 @@ class BookmarkModel : public KeyedService {
     base::string16 title;
   };
 
+  class UndoDelegate {

[sky, 2015/10/07 16:30:15]

Move into it's own header (see chromium specific style guide for details) and
make destructor protected and virtual.

[jianli, 2015/10/07 23:26:55]

Done.

+   public:
+    // Called when a bookmark node was deleted. The delegate takes the ownership
+    // of the deleted node.
+    //
+    // |parent_node_id| the id of the parent of the node that will be removed.
+    // |index| the index of the node about to be removed in |parent|.
+    // |node| is the node to be deleted.
+    virtual void OnBookmarkNodeDeleted(BookmarkModel* model,
+                                       int64_t parent_node_id,

[sky, 2015/10/07 16:30:15]

I would rather supply the BoomarkNode as the parent. If the delegate wants to
track the id, it can.

[jianli, 2015/10/07 23:26:55]

Done.

+                                       int index,
+                                       BookmarkNode* node) = 0;

[sky, 2015/10/07 16:30:15]

Use scoped_ptr to clarify ownership.

[jianli, 2015/10/07 23:26:55]

Done.

+  };
+
   explicit BookmarkModel(BookmarkClient* client);
   ~BookmarkModel() override;
 
@@ -220,6 +234,12 @@ class BookmarkModel : public KeyedService {
       const base::Time& creation_time,
       const BookmarkNode::MetaInfoMap* meta_info);
 
+  // Adds the |node| at |parent| in the specified |index| and notifies its
+  // observers.
+  BookmarkNode* AddNode(BookmarkNode* parent,

[sky, 2015/10/07 16:30:15]

I don't want this to be public. Expose an interface specifically for the
UndoDelegate that BookmarkModel implements.

[jianli, 2015/10/07 23:26:56]

Done.

+                        int index,
+                        BookmarkNode* node);
+
   // Sorts the children of |parent|, notifying observers by way of the
   // BookmarkNodeChildrenReordered method.
   void SortChildren(const BookmarkNode* parent);
@@ -308,6 +328,10 @@ class BookmarkModel : public KeyedService {
   // Returns the client used by this BookmarkModel.
   BookmarkClient* client() const { return client_; }
 
+  void set_undo_delegate(UndoDelegate* undo_delegate) {
+    undo_delegate_ = undo_delegate;
+  }
+
  private:
   friend class BookmarkCodecTest;
   friend class BookmarkModelFaviconTest;
@@ -354,12 +378,6 @@ class BookmarkModel : public KeyedService {
   // Remove |node| from |nodes_ordered_by_url_set_| and |index_|.
   void RemoveNodeFromInternalMaps(BookmarkNode* node);
 
-  // Adds the |node| at |parent| in the specified |index| and notifies its
-  // observers.
-  BookmarkNode* AddNode(BookmarkNode* parent,
-                        int index,
-                        BookmarkNode* node);
-
   // Adds the |node| to |nodes_ordered_by_url_set_| and |index_|.
   void AddNodeToInternalMaps(BookmarkNode* node);
 
@@ -449,6 +467,8 @@ class BookmarkModel : public KeyedService {
 
   std::set<std::string> non_cloned_keys_;
 
+  UndoDelegate* undo_delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(BookmarkModel);
 };