Revert 144115 - Manage IsolatedContext with reference counts

content/browser/child_process_security_policy_impl.cc

Index: content/browser/child_process_security_policy_impl.cc
===================================================================
--- content/browser/child_process_security_policy_impl.cc	(revision 144132)
+++ content/browser/child_process_security_policy_impl.cc	(working copy)
@@ -58,7 +58,7 @@
     for (FileSystemMap::iterator iter = filesystem_permissions_.begin();
          iter != filesystem_permissions_.end();
          ++iter) {
-      isolated_context->RemoveReference(iter->first);
+      isolated_context->RevokeIsolatedFileSystem(iter->first);
     }
     UMA_HISTOGRAM_COUNTS("ChildProcessSecurityPolicy.PerChildFilePermissions",
                          file_permissions_.size());
@@ -97,9 +97,6 @@
   // 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;
   }