[Mac][Material Design] Adjust bookmark spacing and folder menu drawing.

chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_window.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_COCOA_BOOKMARKS_BOOKMARK_BAR_FOLDER_WINDOW_H_
 #define CHROME_BROWSER_UI_COCOA_BOOKMARKS_BOOKMARK_BAR_FOLDER_WINDOW_H_
 
 #import <Cocoa/Cocoa.h>
 
 // Window for a bookmark folder "menu".  This menu pops up when you
 // click on a bookmark button that represents a folder of bookmarks.
 // This window is borderless but has a shadow, at least initially.
 // Once the down scroll arrow is shown, the shadow is turned off and
 // a secondary window is added which is sized to match the visible
 // area of the menu and which provides the shadow.
 @interface BookmarkBarFolderWindow : NSWindow
 @end
 
 // Content view for the above window.  "Stock" other than the drawing
 // of rounded corners.  Only used in the nib.
 @interface BookmarkBarFolderWindowContentView : NSView
+// Returns the folder window's background color (Material Design only).
++ (NSColor*)backgroundColor;
 @end
 
 // Scroll view that contains the main view (where the buttons go).
 @interface BookmarkBarFolderWindowScrollView : NSScrollView
 @end
 
 #endif  // CHROME_BROWSER_UI_COCOA_BOOKMARKS_BOOKMARK_BAR_FOLDER_WINDOW_H_