Adding (empty) placeholder button to 'Other bookmarks' folder is unnecessary.

chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_controller_unittest.mm

 // Copyright (c) 2012 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.
 
 #include "base/basictypes.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_constants.h"
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.h"
@@ skipping 1148 matching lines @@
   [folder removeButton:1 animate:NO];
   EXPECT_NSEQ(@"3b", [[buttons objectAtIndex:0] title]);
   EXPECT_NSEQ(@"2f2b", [[buttons objectAtIndex:1] title]);
   EXPECT_NSEQ(@"2f3b", [[buttons objectAtIndex:2] title]);
   EXPECT_EQ(oldDisplayedButtons, [buttons count]);
 
   // Check button spacing.
   [folder validateMenuSpacing];
 }
 
+TEST_F(BookmarkBarFolderControllerMenuTest, RemoveLastButtonOtherBookmarks) {
+  BookmarkModel* model = BookmarkModelFactory::GetForProfile(profile());
+  const BookmarkNode* otherBookmarks = model->other_node();
+
+  BookmarkButton* otherButton = [bar_ otherBookmarksButton];
+  ASSERT_TRUE(otherButton);
+
+  // Open the folder to get the folderController_.
+  [[otherButton target] performSelector:@selector(openBookmarkFolderFromButton:)

[Alexei Svitkine (slow), 2014/08/21 13:41:42]

Nit: Why performSelector: and not just call the method directly?

[Gaja, 2014/08/21 14:45:43]

In almost all test cases performSelector: has been used when calling
openBookmarkFolderFromButton:. I had built and ran the test case without using
it and worked fine(Test passed). Do you want me to remove it?

[Alexei Svitkine (slow), 2014/08/21 14:48:03]

Yes, please. It's unnecessary. 

[Gaja, 2014/08/21 15:01:24]

Done.

+                             withObject:otherButton];
+  BookmarkBarFolderController* folder = [bar_ folderController];
+  EXPECT_TRUE(folder);
+
+  // Initially there is only (empty) placeholder button, hence buttonCount
+  // should be 1.
+  NSArray* buttons = [folder buttons];
+  EXPECT_TRUE(buttons);
+  EXPECT_EQ(1U, [buttons count]);
+
+  // Add a new bookmark into 'Other bookmarks' folder.
+  model->AddURL(otherBookmarks, otherBookmarks->child_count(),
+                ASCIIToUTF16("TheOther"),
+                GURL("http://www.other.com"));
+
+  // buttonCount still should be 1, as we remove the (empty) placeholder button
+  // when adding a new button to an empty folder.
+  EXPECT_EQ(1U, [buttons count]);
+
+  // Now we have only 1 button; remove it so that 'Other bookmarks' folder
+  // is hidden.
+  [folder removeButton:0 animate:NO];
+  EXPECT_EQ(0U, [buttons count]);
+
+  // 'Other bookmarks' folder gets closed once we remove the last button. Hence
+  // folderController_ should be NULL.
+  EXPECT_FALSE([bar_ folderController]);
+}
+
 TEST_F(BookmarkBarFolderControllerMenuTest, ControllerForNode) {
   BookmarkModel* model = BookmarkModelFactory::GetForProfile(profile());
   const BookmarkNode* root = model->bookmark_bar_node();
   const std::string model_string("1b 2f:[ 2f1b 2f2b ] 3b ");
   test::AddNodesFromModelString(model, root, model_string);
 
   // Validate initial model.
   std::string actualModelString = test::ModelStringFromNode(root);
   EXPECT_EQ(model_string, actualModelString);
 
@@ skipping 424 matching lines @@
   DeleteBookmark([folder parentButton], profile());
   EXPECT_FALSE([folder folderController]);
 }
 
 // TODO(jrg): draggingEntered: and draggingExited: trigger timers so
 // they are hard to test.  Factor out "fire timers" into routines
 // which can be overridden to fire immediately to make behavior
 // confirmable.
 // There is a similar problem with mouseEnteredButton: and
 // mouseExitedButton:.