Add better Bookmark Manager drag and drop stats.

chrome/browser/resources/bookmark_manager/js/dnd.js

 // 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.
 
 cr.define('dnd', function() {
   'use strict';
 
   /** @const */ var BookmarkList = bmm.BookmarkList;
   /** @const */ var ListItem = cr.ui.ListItem;
   /** @const */ var TreeItem = cr.ui.TreeItem;
@@ skipping 327 matching lines @@
 
     if (draggedNodes.length) {
       // If we are dragging a single link, we can do the *Link* effect.
       // Otherwise, we only allow copy and move.
       e.dataTransfer.effectAllowed = draggedNodes.length == 1 &&
           !bmm.isFolder(draggedNodes[0]) ? 'copyMoveLink' : 'copyMove';
 
       chrome.bookmarkManagerPrivate.startDrag(draggedNodes.map(function(node) {
         return node.id;
       }), isFromTouch);
-      chrome.metricsPrivate.recordUserAction('BookmarkManager_StartDrag');
+      var dragTarget = getBookmarkElement(e.target);
+      if (dragTarget instanceof ListItem ||
+          dragTarget instanceof BookmarkList) {
+        chrome.metricsPrivate.recordUserAction(
+            'BookmarkManager_StartDragFromList');
+      } else if (dragTarget instanceof TreeItem) {
+        chrome.metricsPrivate.recordUserAction(
+            'BookmarkManager_StartDragFromTree');
+      }
+
+      chrome.metricsPrivate.recordSmallCount(
+          'BookmarkManager.NumDragged', draggedNodes.length);
     }
   }
 
   function handleDragEnter(e) {
     e.preventDefault();
   }
 
   /**
    * Calback for the dragover event.
    * @param {Event} e The dragover event.
@@ skipping 119 matching lines @@
   function handleDrop(e) {
     var dropInfo = calculateDropInfo(e.target, dropDestination);
     if (dropInfo) {
       selectItemsAfterUserAction(dropInfo.selectTarget,
                                  dropInfo.selectedTreeId);
       if (dropInfo.index != -1)
         chrome.bookmarkManagerPrivate.drop(dropInfo.parentId, dropInfo.index);
       else
         chrome.bookmarkManagerPrivate.drop(dropInfo.parentId);
 
-      chrome.metricsPrivate.recordUserAction('BookmarkManager_Drop');
+      e.preventDefault();
 
-      e.preventDefault();
+      var dragTarget = getBookmarkElement(e.target);
+      var action;
+      if (dragTarget instanceof ListItem ||
+          dragTarget instanceof BookmarkList) {
+        action = 'BookmarkManager_DropToList';
+        if (dropDestination.position == DropPosition.ON)
+          action = 'BookmarkManager_DropToListItem';
+      } else if (dragTarget instanceof TreeItem) {
+        action = 'BookmarkManager_DropToTree';
+        if (dropDestination.position == DropPosition.ON)
+          action = 'BookmarkManager_DropToTreeItem';
+      }
+      if (action)
+        chrome.metricsPrivate.recordUserAction(action);
     }
     dropDestination = null;
     dropIndicator.finish();
   }
 
   function setCurrentTouchTarget(e) {
     // Only set a new target for a single touch point.
     if (e.touches.length == 1)
       currentTouchTarget = getBookmarkElement(e.target);
   }
@@ skipping 27 matching lines @@
     document.addEventListener('touchend', clearCurrentTouchTarget);
     document.addEventListener('touchstart', setCurrentTouchTarget);
 
     chrome.bookmarkManagerPrivate.onDragEnter.addListener(
         dragInfo.handleChromeDragEnter);
     chrome.bookmarkManagerPrivate.onDragLeave.addListener(deferredClearData);
     chrome.bookmarkManagerPrivate.onDrop.addListener(deferredClearData);
   }
   return {init: init};
 });