downloads: clicking "remove" on chrome://downloads should also hide shelf item.

chrome/browser/download/test_download_shelf.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_TEST_DOWNLOAD_SHELF_H_
 #define CHROME_BROWSER_DOWNLOAD_TEST_DOWNLOAD_SHELF_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/download/download_shelf.h"
 #include "content/public/browser/download_manager.h"
 
 // An implementation of DownloadShelf for testing.
 class TestDownloadShelf : public DownloadShelf,
                           public content::DownloadManager::Observer {
  public:
   TestDownloadShelf();
   ~TestDownloadShelf() override;
 
   // DownloadShelf:
+  void RemoveDownload(content::DownloadItem* download) override;
   bool IsShowing() const override;
   bool IsClosing() const override;
   Browser* browser() const override;
 
   // Return |true| if a download was added to this shelf.
   bool did_add_download() const { return did_add_download_; }
 
   // Set download_manager_ (and the result of calling GetDownloadManager())
   void set_download_manager(content::DownloadManager* download_manager);
 
   // DownloadManager::Observer implementation.
   void ManagerGoingDown(content::DownloadManager* manager) override;
 
  protected:
   void DoAddDownload(content::DownloadItem* download) override;
   void DoShow() override;
   void DoClose(CloseReason reason) override;
   base::TimeDelta GetTransientDownloadShowDelay() override;
   content::DownloadManager* GetDownloadManager() override;
 
  private:
   bool is_showing_;
   bool did_add_download_;
   content::DownloadManager* download_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(TestDownloadShelf);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_TEST_DOWNLOAD_SHELF_H_