Revert 176015

chrome/browser/extensions/api/storage/value_store_cache.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_EXTENSIONS_API_STORAGE_VALUE_STORE_CACHE_H_
-#define CHROME_BROWSER_EXTENSIONS_API_STORAGE_VALUE_STORE_CACHE_H_
-
-#include <string>
-
-#include "base/callback.h"
-#include "base/memory/ref_counted.h"
-
-class ValueStore;
-
-namespace extensions {
-
-class Extension;
-
-// Each namespace of the storage API implements this interface.
-// Instances are created on the UI thread, but from then on live on the FILE
-// thread. At shutdown, ShutdownOnUI() is first invoked on the UI thread, and
-// the destructor is invoked soon after on the FILE thread. This gives
-// implementations the chance to work with ValueStores on FILE but observe
-// events on UI.
-// It also means that any methods invoked on UI *before ShutdownOnUI()* can
-// safely post other methods to the FILE thread, since the deletion task is only
-// posted to FILE after ShutdownOnUI().
-class ValueStoreCache {
- public:
-  typedef base::Callback<void(ValueStore*)> StorageCallback;
-
-  // Invoked on FILE.
-  virtual ~ValueStoreCache();
-
-  // This is invoked from the UI thread during destruction of the Profile that
-  // ultimately owns this object. Any Profile-related cleanups should be
-  // performed in this method, since the destructor will execute later, after
-  // the Profile is already gone.
-  virtual void ShutdownOnUI();
-
-  // Requests the cache to invoke |callback| with the appropriate ValueStore
-  // for the given |extension|. |callback| should be invoked with a NULL
-  // ValueStore in case of errors.
-  // |extension| is passed in a scoped_refptr<> because this method is
-  // asynchronously posted as a task to the loop returned by GetMessageLoop(),
-  // and this guarantees the Extension is still valid when the method executes.
-  virtual void RunWithValueStoreForExtension(
-      const StorageCallback& callback,
-      scoped_refptr<const Extension> extension) = 0;
-
-  // Requests the cache to delete any storage used by |extension_id|.
-  virtual void DeleteStorageSoon(const std::string& extension_id) = 0;
-};
-
-}  // namespace extensions
-
-#endif  // CHROME_BROWSER_EXTENSIONS_API_STORAGE_VALUE_STORE_CACHE_H_