Eliminate Bookmarks dependence to bookmark_undo_utils.h.

chrome/browser/bookmarks/bookmark_model_observer.h

Index: chrome/browser/bookmarks/bookmark_model_observer.h
diff --git a/chrome/browser/bookmarks/bookmark_model_observer.h b/chrome/browser/bookmarks/bookmark_model_observer.h
index d9116e82ea5f3a8039611343353e30d2f0a0bdda..e03e65d1c6605ba4cd28bd1f3e562f3e4692ec3e 100644
--- a/chrome/browser/bookmarks/bookmark_model_observer.h
+++ b/chrome/browser/bookmarks/bookmark_model_observer.h
@@ -99,6 +99,15 @@ class BookmarkModelObserver {
   // Invoked when all non-permanent bookmark nodes have been removed.
   virtual void BookmarkAllNodesRemoved(BookmarkModel* model) = 0;
 
+  // Invoked before a set of model changes that is initiated by a single user
+  // action. For example, this is called a single time when pasting from the
+  // clipboard before each pasted bookmark is added to the bookmark model.
+  virtual void GroupedBookmarkChangesBeginning(BookmarkModel* model) {}
+
+  // Invoked after a set of model changes triggered by a single user action has
+  // ended.
+  virtual void GroupedBookmarkChangesEnded(BookmarkModel* model) {}
+
  protected:
   virtual ~BookmarkModelObserver() {}
 };