Add isWritableFileEntry to the fileSystem API

content/browser/child_process_security_policy_impl.cc

 // 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.
 
 #include "content/browser/child_process_security_policy_impl.h"
 
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/platform_file.h"
@@ skipping 507 matching lines @@
                                kEnumerateDirectoryPermissions);
 }
 
 bool ChildProcessSecurityPolicyImpl::CanReadFileSystem(
     int child_id, const std::string& filesystem_id) {
   return HasPermissionsForFileSystem(child_id,
                                      filesystem_id,
                                      kReadFilePermissions);
 }
 
+bool ChildProcessSecurityPolicyImpl::CanReadWriteFileSystem(
+    int child_id, const std::string& filesystem_id) {
+  return HasPermissionsForFileSystem(child_id,
+                                     filesystem_id,
+                                     kReadFilePermissions |
+                                     kWriteFilePermissions);
+}
+
 bool ChildProcessSecurityPolicyImpl::HasPermissionsForFile(
     int child_id, const FilePath& file, int permissions) {
   base::AutoLock lock(lock_);
   bool result = ChildProcessHasPermissionsForFile(child_id, file, permissions);
   if (!result) {
     // If this is a worker thread that has no access to a given file,
     // let's check that its renderer process has access to that file instead.
     WorkerToMainProcessMap::iterator iter = worker_map_.find(child_id);
     if (iter != worker_map_.end() && iter->second != 0) {
       result = ChildProcessHasPermissionsForFile(iter->second,
@@ skipping 76 matching lines @@
     int child_id,
     const std::string& filesystem_id,
     int permission) {
   base::AutoLock lock(lock_);
 
   SecurityStateMap::iterator state = security_state_.find(child_id);
   if (state == security_state_.end())
     return false;
   return state->second->HasPermissionsForFileSystem(filesystem_id, permission);
 }