Change infobar creation to use a public static Create() method on the infobar delegate classes.

chrome/browser/download/download_request_infobar_delegate.h

 // 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.
 
 #ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_INFOBAR_DELEGATE_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_INFOBAR_DELEGATE_H_
 
 #include "base/basictypes.h"
 #include "chrome/browser/api/infobars/confirm_infobar_delegate.h"
 #include "chrome/browser/download/download_request_limiter.h"
 
 class InfoBarService;
 
 // An infobar delegate that presents the user with a choice to allow or deny
 // multiple downloads from the same site. This confirmation step protects
 // against "carpet-bombing", where a malicious site forces multiple downloads
 // on an unsuspecting user.
 class DownloadRequestInfoBarDelegate : public ConfirmInfoBarDelegate {
  public:
-  DownloadRequestInfoBarDelegate(
-      InfoBarService* infobar_service,
-      DownloadRequestLimiter::TabDownloadState* host);
+  virtual ~DownloadRequestInfoBarDelegate();
+
+  // Creates a download request delegate and adds it to |infobar_service|.
+  static void Create(InfoBarService* infobar_service,
+                     DownloadRequestLimiter::TabDownloadState* host);
+
+#if defined(UNIT_TEST)
+  static scoped_ptr<DownloadRequestInfoBarDelegate> Create(
+      DownloadRequestLimiter::TabDownloadState* host) {
+    return scoped_ptr<DownloadRequestInfoBarDelegate>(
+        new DownloadRequestInfoBarDelegate(NULL, host));
+  }
+#endif
 
   void set_host(DownloadRequestLimiter::TabDownloadState* host) {
     host_ = host;
   }
 
  private:
-  virtual ~DownloadRequestInfoBarDelegate();
+  DownloadRequestInfoBarDelegate(
+      InfoBarService* infobar_service,
+      DownloadRequestLimiter::TabDownloadState* host);
 
   // ConfirmInfoBarDelegate:
   virtual gfx::Image* GetIcon() const OVERRIDE;
   virtual string16 GetMessageText() const OVERRIDE;
   virtual string16 GetButtonLabel(InfoBarButton button) const OVERRIDE;
   virtual bool Accept() OVERRIDE;
 
   DownloadRequestLimiter::TabDownloadState* host_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadRequestInfoBarDelegate);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_REQUEST_INFOBAR_DELEGATE_H_