Manage IsolatedContext with reference counts

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 40 matching lines @@
     : enabled_bindings_(0),
       can_read_raw_cookies_(false) { }
 
   ~SecurityState() {
     scheme_policy_.clear();
     fileapi::IsolatedContext* isolated_context =
         fileapi::IsolatedContext::GetInstance();
     for (FileSystemMap::iterator iter = filesystem_permissions_.begin();
          iter != filesystem_permissions_.end();
          ++iter) {
-      isolated_context->RevokeIsolatedFileSystem(iter->first);
+      isolated_context->RemoveReference(iter->first);
     }
     UMA_HISTOGRAM_COUNTS("ChildProcessSecurityPolicy.PerChildFilePermissions",
                          file_permissions_.size());
   }
 
   // Grant permission to request URLs with the specified scheme.
   void GrantScheme(const std::string& scheme) {
     scheme_policy_[scheme] = true;
   }
 
@@ skipping 18 matching lines @@
   // Revokes all permissions granted to a file.
   void RevokeAllPermissionsForFile(const FilePath& file) {
     FilePath stripped = file.StripTrailingSeparators();
     file_permissions_.erase(stripped);
     request_file_set_.erase(stripped);
   }
 
   // Grant certain permissions to a file.
   void GrantPermissionsForFileSystem(const std::string& filesystem_id,
                                      int permissions) {
+    if (filesystem_permissions_.find(filesystem_id) ==
+        filesystem_permissions_.end())
+      fileapi::IsolatedContext::GetInstance()->AddReference(filesystem_id);
     filesystem_permissions_[filesystem_id] = permissions;
   }
 
   bool HasPermissionsForFileSystem(const std::string& filesystem_id,
                                    int permissions) {
     if (filesystem_permissions_.find(filesystem_id) ==
         filesystem_permissions_.end())
       return false;
     return (filesystem_permissions_[filesystem_id] & permissions) ==
         permissions;
@@ skipping 502 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);
 }