Fix an ordering issue with dragging multiple selected bookmarks.

When dragging a multi-selection of bookmarks in the manager, the order
of the selected bookmarks became the order of the selection instead of
their original displaying order.

This CL updates the order of dragged nodes to the displaying order.

BUG=794886

Change-Id: I4ab3ead0454874eee9e7dc49522156aba27f10d4
Reviewed-on: https://chromium-review.googlesource.com/c/1349130Reviewed-by: calamity <calamity@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Maggie Cai <mxcai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613009}

chrome/browser/resources/md_bookmarks/dnd_manager.js

@@ -376,7 +376,26 @@ cr.define('bookmarks', function() {
       }
 
       const state = bookmarks.Store.getInstance().data;
-      const draggedNodes = dragData.elements.map((item) => item.id);
+
+      let draggedNodes = [];
+
+      if (isBookmarkItem(dragElement)) {
+        const displayingItems =
+            assert(state.nodes[state.selectedFolder].children);
+
+        for (const itemId of displayingItems) {
+          for (const element of dragData.elements) {
+            if (element.id == itemId) {
+              draggedNodes.push(element.id);
+            }
+          }
+        }
+      } else {
+        draggedNodes = dragData.elements.map((item) => item.id);
+      }
+
+      assert(draggedNodes.length == dragData.elements.length);
+
       const dragNodeIndex = draggedNodes.indexOf(dragElement.itemId);
       assert(dragNodeIndex != -1);
 

chrome/browser/resources/md_bookmarks/list.js

@@ -178,7 +178,9 @@ Polymer({
     const toHighlight = /** @type {!Array<string>} */
         (e.detail.filter((item) => this.displayedIds_.indexOf(item) != -1));
 
-    assert(toHighlight.length > 0);
+    if (toHighlight.length <= 0)
+      return;
+
     const leadId = toHighlight[0];
     this.dispatch(
         bookmarks.actions.selectAll(toHighlight, this.getState(), leadId));