MD Bookmarks: Add 'Open' command, to open in either the BMM or in new tabs

chrome/browser/resources/md_bookmarks/item.js

 // Copyright 2016 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.
 
 Polymer({
   is: 'bookmarks-item',
 
   behaviors: [
     bookmarks.StoreClient,
   ],
@@ skipping 11 matching lines @@
     },
 
     /** @private */
     isSelectedItem_: {
       type: Boolean,
       reflectToAttribute: true,
     },
 
     /** @private */
     isFolder_: Boolean,
+
+    /** @private */
+    openItemUrl_: String,
   },
 
   observers: [
     'updateFavicon_(item_.url)',
   ],
 
   listeners: {
     'click': 'onClick_',
     'dblclick': 'onDblClick_',
     'contextmenu': 'onContextMenu_',
@@ skipping 57 matching lines @@
   onItemIdChanged_: function() {
     // TODO(tsergeant): Add a histogram to measure whether this assertion fails
     // for real users.
     assert(this.getState().nodes[this.itemId]);
     this.updateFromStore();
   },
 
   /** @private */
   onItemChanged_: function() {
     this.isFolder_ = !this.item_.url;
+    if (this.item_.url)
+      this.openItemUrl_ = this.item_.url;
+    else
+      this.openItemUrl_ = 'chrome://bookmarks/?id=' + this.itemId;
   },
 
   /**
-   * @param {Event} e
+   * @param {MouseEvent} e
    * @private
    */
   onClick_: function(e) {
-    this.dispatch(bookmarks.actions.selectItem(
-        this.itemId, e.ctrlKey, e.shiftKey, this.getState()));
+    if (e.detail == 1) {

[calamity, 2017/05/17 05:09:23]

Comment explaining what this is for. (What _is_ this for?)

[tsergeant, 2017/05/17 07:04:38]

When you double click, the browser fires two click events and then a dblclick
event.

If you shift double clicked an item, the following would happen:

1. First click event selects the range, as expected
2. Second click event deselects the range and only selects the clicked item,
because the anchor has moved to the clicked item
3. dblclick event opens the clicked item instead of the full range of items.

This was a fix to that issue by preventing the second click event from
happening.

HOWEVER, I think that's not quite what we want after all. The root issue is that
the anchor shouldn't change when shift is held down. This matches Windows
Explorer and the old BMM. If the anchor doesn't change, then the second click
event will not change the selection.

I've gone ahead and made that change to selectItem(). As an extra benefit, this
will allow ctrl-doubleclick to work correctly down the line.

[calamity, 2017/05/19 03:47:58]

Acknowledged.

+      this.dispatch(bookmarks.actions.selectItem(
+          this.itemId, e.ctrlKey, e.shiftKey, this.getState()));
+    }
     e.stopPropagation();
+    e.preventDefault();
   },
 
   /**
-   * @param {Event} e
+   * @param {MouseEvent} e
    * @private
    */
   onDblClick_: function(e) {
-    if (!this.item_.url) {
-      this.dispatch(
-          bookmarks.actions.selectFolder(this.item_.id, this.getState().nodes));
-    } else {
-      chrome.tabs.create({url: this.item_.url});
-    }
+    var commandManager = bookmarks.CommandManager.getInstance();
+    var itemSet = this.getState().selection.items;
+    if (commandManager.canExecute(Command.OPEN, itemSet))
+      commandManager.handle(Command.OPEN, itemSet);
   },
 
   /**
    * @param {string} url
    * @private
    */
   updateFavicon_: function(url) {
     this.$.icon.style.backgroundImage = cr.icon.getFavicon(url);
   },
 });