CoreAnimation: Fix text anti-aliasing in download shelf

chrome/browser/ui/cocoa/download/download_show_all_button.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/download/download_show_all_button.h"
 
 #include "base/logging.h"
 #import "chrome/browser/ui/cocoa/download/download_show_all_cell.h"
+#import "chrome/browser/ui/cocoa/nsview_additions.h"
+#import "chrome/browser/ui/cocoa/view_id_util.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image.h"
 
 @implementation DownloadShowAllButton
 
 - (void)awakeFromNib {
   DCHECK([[self cell] isKindOfClass:[DownloadShowAllCell class]]);
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   NSImage* favicon = rb.GetNativeImageNamed(IDR_DOWNLOADS_FAVICON).ToNSImage();
   [self setImage:favicon];
 }
 
 // GTM's layout tweaker calls sizeToFit to receive the desired width of views.
 // By default, buttons will be only 14px high, but the Show All button needs to
 // be higher.
 - (void)sizeToFit {
   NSRect oldRect = [self frame];
   [super sizeToFit];
   NSRect newRect = [self frame];
 
   // Keep old height.
   newRect.origin.y = oldRect.origin.y;
   newRect.size.height = oldRect.size.height;
 
   [self setFrame:newRect];
 }
 
+- (BOOL)isOpaque {
+  // Make this control opaque so that sub-pixel anti-aliasing works when
+  // CoreAnimation is enabled.
+  return YES;
+}
+
+- (void)drawRect:(NSRect)rect {
+  NSView* downloadShelfView = [self ancestorWithViewID:VIEW_ID_DOWNLOAD_SHELF];
+  [self cr_drawUsingAncestor:downloadShelfView inRect:rect];
+  [super drawRect:rect];
+}
+
 @end