Use the managed bookmarks icon for its folder on Mac.

chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.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.
 
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.h"
 
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
@@ skipping 564 matching lines @@
   }
 
   // In general, only show the divider when it's in the normal showing state.
   return [self isInState:BookmarkBar::SHOW] ? 0 : 1;
 }
 
 - (NSImage*)faviconForNode:(const BookmarkNode*)node {
   if (!node)
     return defaultImage_;
 
-  // TODO(joaodasilva): return the "Managed Bookmarks" icon here for the
-  // managed node.
+  if (node == bookmarkClient_->managed_node()) {
+    // Most users never see this node, so the image is only loaded if needed.
+    ResourceBundle& rb = ResourceBundle::GetSharedInstance();
+    return rb.GetNativeImageNamed(IDR_BOOKMARK_BAR_FOLDER_MANAGED).ToNSImage();
+  }
+
   if (node->is_folder())
     return folderImage_;
 
   const gfx::Image& favicon = bookmarkModel_->GetFavicon(node);
   if (!favicon.IsEmpty())
     return favicon.ToNSImage();
 
   return defaultImage_;
 }
 
@@ skipping 2194 matching lines @@
 - (id<BookmarkButtonControllerProtocol>)controllerForNode:
     (const BookmarkNode*)node {
   // See if it's in the bar, then if it is in the hierarchy of visible
   // folder menus.
   if (bookmarkModel_->bookmark_bar_node() == node)
     return self;
   return [folderController_ controllerForNode:node];
 }
 
 @end