Revert of Rate limit programmatic update checks for extensions

extensions/browser/updater/extension_downloader_test_delegate.h

-// Copyright 2016 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 EXTENSIONS_BROWSER_UPDATER_EXTENSION_DOWNLOADER_TEST_DELEGATE_H_
-#define EXTENSIONS_BROWSER_UPDATER_EXTENSION_DOWNLOADER_TEST_DELEGATE_H_
-
-#include <memory>
-
-namespace extensions {
-
-class ExtensionDownloader;
-class ExtensionDownloaderDelegate;
-class ManifestFetchData;
-
-// A class for intercepting the work of checking for / downloading extension
-// updates.
-class ExtensionDownloaderTestDelegate {
- public:
-  // This method gets called when an update check is being started for an
-  // extension. Normally implementors should eventually call either
-  // OnExtensionDownloadFailed or OnExtensionDownloadFinished on
-  // |delegate|.
-  virtual void StartUpdateCheck(
-      ExtensionDownloader* downloader,
-      ExtensionDownloaderDelegate* delegate,
-      std::unique_ptr<ManifestFetchData> fetch_data) = 0;
-};
-
-}  // namespace extensions
-
-#endif  // EXTENSIONS_BROWSER_UPDATER_EXTENSION_DOWNLOADER_TEST_DELEGATE_H_