Add UMA stats for tracking bookmark depth

chrome/browser/bookmarks/bookmark_stats.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_BOOKMARKS_BOOKMARK_STATS_H_
 #define CHROME_BROWSER_BOOKMARKS_BOOKMARK_STATS_H_
 
+class BookmarkNode;
+
 // This enum is used for the Bookmarks.EntryPoint histogram.
 enum BookmarkEntryPoint {
   BOOKMARK_ENTRY_POINT_ACCELERATOR,
   BOOKMARK_ENTRY_POINT_STAR_GESTURE,
   BOOKMARK_ENTRY_POINT_STAR_KEY,
   BOOKMARK_ENTRY_POINT_STAR_MOUSE,
 
   BOOKMARK_ENTRY_POINT_LIMIT // Keep this last.
 };
 
@@ skipping 13 matching lines @@
   BOOKMARK_LAUNCH_LOCATION_WRENCH_MENU,
   // Bookmark manager.
   BOOKMARK_LAUNCH_LOCATION_MANAGER,
   // Autocomplete suggestion.
   BOOKMARK_LAUNCH_LOCATION_OMNIBOX,
 
   BOOKMARK_LAUNCH_LOCATION_LIMIT  // Keep this last.
 };
 
 // Records the launch of a bookmark for UMA purposes.
-void RecordBookmarkLaunch(BookmarkLaunchLocation location);
+void RecordBookmarkLaunch(const BookmarkNode* node,
+                          BookmarkLaunchLocation location);
 
 // Records the user opening a folder of bookmarks for UMA purposes.
 void RecordBookmarkFolderOpen(BookmarkLaunchLocation location);
 
 // Records the user opening the apps page for UMA purposes.
 void RecordBookmarkAppsPageOpen(BookmarkLaunchLocation location);
 
 #endif  // CHROME_BROWSER_BOOKMARKS_BOOKMARK_STATS_H_