A few minor changes to the chrome.downloads extension API

chrome/browser/download/download_danger_prompt.h

 // 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.
 
 #ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_DANGER_PROMPT_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_DANGER_PROMPT_H_
 
 #include "base/callback_forward.h"
 
 namespace content {
 class DownloadItem;
 class WebContents;
 }
 
 // Prompts the user for whether to Keep a dangerous DownloadItem using native
 // UI. This prompt is invoked by the DownloadsDOMHandler when the user wants to
 // accept a dangerous download. Having a native dialog intervene during the this
 // workflow means that the chrome://downloads page no longer has the privilege
 // to accept a dangerous download from script without user intervention. This
 // step is necessary to prevent a malicious script form abusing such a
 // privilege.
 class DownloadDangerPrompt {
  public:
   // Actions resulting from showing the danger prompt.
   enum Action {
     ACCEPT,
-    CANCEL
+    CANCEL,
+    DISMISS,
   };
+  typedef base::Callback<void(Action)> OnDone;
 
   // Return a new self-deleting DownloadDangerPrompt. |accepted| or |canceled|
   // will be run when the the respective action is invoked. |canceled| may also
   // be called when |item| is either no longer dangerous or no longer in
   // progress, or if the tab corresponding to |web_contents| is
   // closing. The returned DownloadDangerPrompt* is only used for testing. The
   // caller does not own the object and receive no guarantees about lifetime.
   // If |show_context|, then the prompt message will contain some information
   // about the download and its danger; otherwise it won't.
   static DownloadDangerPrompt* Create(
       content::DownloadItem* item,
       content::WebContents* web_contents,
       bool show_context,
-      const base::Closure& accepted,
-      const base::Closure& canceled);
+      const OnDone& done);
 
  protected:
   friend class DownloadDangerPromptTest;
 
   // Only to be used by tests. Subclasses must override to manually call the
   // respective button click handler.
   virtual void InvokeActionForTesting(Action action) = 0;
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_DANGER_PROMPT_H_