CoreAnimation: Fix text anti-aliasing in download shelf

chrome/browser/ui/cocoa/view_id_util.mm

 // Copyright (c) 2011 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/view_id_util.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include <map>
 #include <utility>
@@ skipping 68 matching lines @@
 }  // namespace view_id_util
 
 @implementation NSView (ViewID)
 
 - (ViewID)viewID {
   ViewIDMap* map = g_view_id_map.Pointer();
   ViewIDMap::const_iterator iter = map->find(self);
   return iter != map->end() ? iter->second : VIEW_ID_NONE;
 }
 
+- (NSView*)ancestorWithViewID:(ViewID)viewID {
+  NSView* ancestor = self;
+  while (ancestor && [ancestor viewID] != viewID)
+    ancestor = [ancestor superview];
+  return ancestor;
+}
+
 @end