Download shelf autohides on showing in shell, just same as regular open

chrome/browser/ui/cocoa/download/download_item_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/download/download_item_controller.h"
 
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string16.h"
@@ skipping 221 matching lines @@
 
   NSView* view = [self view];
   NSRect containerFrame = [[view superview] frame];
   [view setHidden:(NSMaxX([view frame]) > NSWidth(containerFrame))];
 }
 
 - (void)downloadWasOpened {
   [shelf_ downloadWasOpened:self];
 }
 
+- (void)downloadWasShown {
+  [shelf_ downloadWasShown:self];
+}
+
 - (IBAction)handleButtonClick:(id)sender {
   NSEvent* event = [NSApp currentEvent];
   DownloadItem* download = [self download];
   if ([event modifierFlags] & NSCommandKeyMask) {
     // Let cmd-click show the file in Finder, like e.g. in Safari and Spotlight.
     download->ShowDownloadInShell();
   } else {
     download->OpenDownload();
   }
 }
 
 - (NSSize)preferredSize {
   if (state_ == kNormal)
     return [progressView_ frame].size;
   DCHECK_EQ(kDangerous, state_);
   return [dangerousDownloadView_ frame].size;
 }
 
 - (DownloadItem*)download {
   return bridge_->download_model()->download();
 }
 
+- (DownloadItemModel*)downloadItemModel{
+  return bridge_->download_model();

[asanka, 2014/06/12 21:08:47]

This method shouldn't be necessary. If you have a DownloadItem*, you can always
create a DownloadItemModel using it.

+}
+
 - (ui::MenuModel*)contextMenuModel {
   return menuBridge_->GetMenuModel();
 }
 
 - (void)updateToolTip {
   base::string16 tooltip_text =
       bridge_->download_model()->GetTooltipText(*font_list_, kToolTipMaxWidth);
   [progressView_ setToolTip:base::SysUTF16ToNSString(tooltip_text)];
 }
 
@@ skipping 67 matching lines @@
   base::scoped_nsobject<DownloadShelfContextMenuController> menuController(
       [[DownloadShelfContextMenuController alloc]
         initWithItemController:self
                   withDelegate:nil]);
   [NSMenu popUpContextMenu:[menuController menu]
                  withEvent:[NSApp currentEvent]
                    forView:[self view]];
 }
 
 @end