MD Bookmarks: Enable the delete button in the toolbar overlay

chrome/test/data/webui/md_bookmarks/toolbar_test.js

Index: chrome/test/data/webui/md_bookmarks/toolbar_test.js
diff --git a/chrome/test/data/webui/md_bookmarks/toolbar_test.js b/chrome/test/data/webui/md_bookmarks/toolbar_test.js
index 1cd78ffb9c9a0bae3d3f9f503ffb0e212e8e7ca5..500298c49622fc1e088345d7d9ff23bac44eb785 100644
--- a/chrome/test/data/webui/md_bookmarks/toolbar_test.js
+++ b/chrome/test/data/webui/md_bookmarks/toolbar_test.js
@@ -5,6 +5,7 @@
 suite('<bookmarks-toolbar>', function() {
   var toolbar;
   var store;
+  var commandManager;
 
   setup(function() {
     store = new bookmarks.TestStore({
@@ -21,6 +22,9 @@ suite('<bookmarks-toolbar>', function() {
 
     toolbar = document.createElement('bookmarks-toolbar');
     replaceBody(toolbar);
+
+    commandManager = new TestCommandManager();

[calamity, 2017/05/23 03:42:55]

Does this also need to get assigned to bookmarks.CommandManager.instance_? It
might be worth putting it in the TestCommandManager() constructor, or at least a
method (e.g HijackSingleton()).

Same with TestStore. 

[tsergeant, 2017/05/23 04:11:36]

CommandManager is a bit weird, because it takes over the singleton for itself
during attached:
https://cs.chromium.org/chromium/src/chrome/browser/resources/md_bookmarks/co...

That means that appending it to the body (and removing it during cleanup) will
automatically take care of the singleton.

However, I don't think we want to do this in the constructor automatically, in
case the test is doing something careful with the body.

Do you agree? Do you still want me to change TestStore anyway?

[calamity, 2017/05/23 05:34:19]

Oh yeah, I totally forgot about that subtlety.
We can defer this I think.

+    document.body.appendChild(commandManager);
   });
 
   test('selecting multiple items shows toolbar overlay', function() {
@@ -34,4 +38,15 @@ suite('<bookmarks-toolbar>', function() {
     store.notifyObservers();
     assertTrue(toolbar.showSelectionOverlay);
   });
+
+  test('clicking overlay delete button triggers a delete command', function() {
+    store.data.selection.items = new Set(['2', '3']);
+    store.notifyObservers();
+
+    Polymer.dom.flush();
+    MockInteractions.tap(
+        toolbar.$$('cr-toolbar-selection-overlay').deleteButton);
+
+    commandManager.assertLastCommand(Command.DELETE, ['2', '3']);
+  });
 });