Make quota logic obey durable storage permission

extensions/shell/browser/shell_special_storage_policy.cc

 // Copyright 2014 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.
 
 #include "extensions/shell/browser/shell_special_storage_policy.h"
 
 namespace extensions {
 
 ShellSpecialStoragePolicy::ShellSpecialStoragePolicy() {
 }
 
 ShellSpecialStoragePolicy::~ShellSpecialStoragePolicy() {
 }
 
 bool ShellSpecialStoragePolicy::IsStorageProtected(const GURL& origin) {
   return true;
 }
 
 bool ShellSpecialStoragePolicy::IsStorageUnlimited(const GURL& origin) {
   return true;
 }
 
+bool ShellSpecialStoragePolicy::IsStorageDurable(const GURL& origin) {
+  // The plan is to forbid extensions from acquiring the durable storage
+  // permission because they can specify 'unlimitedStorage' in the manifest.
+  return false;
+}
+
 bool ShellSpecialStoragePolicy::IsStorageSessionOnly(const GURL& origin) {
   return false;
 }
 
 bool ShellSpecialStoragePolicy::CanQueryDiskSize(const GURL& origin) {
   return true;
 }
 
 bool ShellSpecialStoragePolicy::HasSessionOnlyOrigins() {
   return false;
 }
 
 bool ShellSpecialStoragePolicy::HasIsolatedStorage(const GURL& origin) {
   return false;
 }
 
 }  // namespace extensions