[Mac] Fix a crash in handling keyboard shortcuts for empty bookmark folder menus.

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 <cmath>
 
 #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"
@@ skipping 1375 matching lines @@
   [bbfc mouseEnteredButton:button event:nil];
   buttonThatMouseIsIn = [bbfc buttonThatMouseIsIn];
   EXPECT_EQ(button, buttonThatMouseIsIn);
 
   // Delete the bookmark and verify that it is now not known.
   model->Remove(folder->GetChild(3));
   buttonThatMouseIsIn = [bbfc buttonThatMouseIsIn];
   EXPECT_FALSE(buttonThatMouseIsIn);
 }
 
+// Tests that sending keyboard events to the (empty) button in an empty
+// folder menu does not crash. https://crbug.com/690424
+TEST_F(BookmarkBarFolderControllerMenuTest, ActOnEmptyMenu) {
+  BookmarkModel* model = BookmarkModelFactory::GetForBrowserContext(profile());
+  const BookmarkNode* root = model->bookmark_bar_node();
+  const BookmarkNode* folder =
+      model->AddFolder(root, root->child_count(), ASCIIToUTF16("empty"));
+  ASSERT_TRUE(folder);
+
+  BookmarkButton* button = [bar_ buttonWithTitleEqualTo:@"empty"];
+  [[button target] performSelector:@selector(openBookmarkFolderFromButton:)
+                        withObject:button];
+
+  BookmarkBarFolderController* bbfc = [bar_ folderController];
+  NSArray* buttons = [bbfc buttons];
+  ASSERT_EQ(1u, [buttons count]);
+
+  button = [buttons objectAtIndex:0];
+  EXPECT_TRUE([button isEmpty]);
+
+  [bbfc mouseEnteredButton:button event:nil];
+
+  EXPECT_TRUE([bbfc handleInputText:@" "]);
+}
+
 // Just like a BookmarkBarFolderController but intercedes when providing
 // pasteboard drag data.
 @interface BookmarkBarFolderControllerDragData : BookmarkBarFolderController {
   const BookmarkNode* dragDataNode_;  // Weak
 }
 - (void)setDragDataNode:(const BookmarkNode*)node;
 @end
 
 @implementation BookmarkBarFolderControllerDragData
 
@@ skipping 293 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:.