Add extensions code to use common updater in components/update_client/

extensions/browser/updater/update_data_provider.h

+// Copyright 2015 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_UPDATE_DATA_PROVIDER_H_
+#define EXTENSIONS_BROWSER_UPDATER_UPDATE_DATA_PROVIDER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace content {
+class BrowserContext;
+}
+
+namespace update_client {
+struct CrxComponent;
+}
+
+namespace extensions {
+
+// This class exists to let an UpdateClient retrieve information about a set of
+// extensions it is doing an update check for.
+class UpdateDataProvider : public base::RefCounted<UpdateDataProvider> {
+ public:
+  typedef base::Callback<void(content::BrowserContext* context,
+                              const std::string& /* extension_id */,
+                              const base::FilePath& /* temp_dir */)>
+      InstallCallback;
+
+  // We need a browser context to use when retrieving data for a set of
+  // extension ids, as well as a callback for proceeding with installation
+  // steps once the UpdateClient has downloaded and unpacked an update for an
+  // extension.
+  UpdateDataProvider(content::BrowserContext* context,
+                     const InstallCallback& callback);
+
+  // Notify this object that the associated browser context is being shut down
+  // the pointer to the context should be dropped and no more work should be
+  // done.
+  void Shutdown();
+
+  // Matches update_client::UpdateClient::CrxDataCallback
+  void GetData(const std::vector<std::string>& ids,
+               std::vector<update_client::CrxComponent>* data);
+
+ private:
+  friend class base::RefCounted<UpdateDataProvider>;
+  ~UpdateDataProvider();
+
+  void RunInstallCallback(const std::string& extension_id,
+                          const base::FilePath& temp_dir);
+
+  content::BrowserContext* context_;
+  InstallCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(UpdateDataProvider);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_UPDATER_UPDATE_DATA_PROVIDER_H_