Extensions: Clarify ManifestHandler interface expectations.

extensions/common/manifest_handler.cc

 // Copyright (c) 2013 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/common/manifest_handler.h"
 
 #include <stddef.h>
 
 #include <map>
 
 #include "base/logging.h"
 #include "base/stl_util.h"
+#include "base/threading/thread_restrictions.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/permissions/manifest_permission.h"
 #include "extensions/common/permissions/manifest_permission_set.h"
 
 namespace extensions {
 
 namespace {
 
 static base::LazyInstance<ManifestHandlerRegistry>::DestructorAtExit
     g_registry = LAZY_INSTANCE_INITIALIZER;
@@ skipping 60 matching lines @@
 // static
 bool ManifestHandler::ParseExtension(Extension* extension,
                                      base::string16* error) {
   return GetRegistry()->ParseExtension(extension, error);
 }
 
 // static
 bool ManifestHandler::ValidateExtension(const Extension* extension,
                                         std::string* error,
                                         std::vector<InstallWarning>* warnings) {
+  base::ThreadRestrictions::AssertIOAllowed();

[lazyboy, 2017/04/26 22:06:53]

Can we put the IO comment for this function too in the header?

[karandeepb, 2017/04/26 22:19:59]

Done.

   return GetRegistry()->ValidateExtension(extension, error, warnings);
 }
 
 // static
 ManifestPermission* ManifestHandler::CreatePermission(const std::string& name) {
   return GetRegistry()->CreatePermission(name);
 }
 
 // static
 void ManifestHandler::AddExtensionInitialRequiredPermissions(
@@ skipping 140 matching lines @@
     unsorted_handlers.swap(next_unsorted_handlers);
   }
 
   // If there are any leftover unsorted handlers, they must have had
   // circular dependencies.
   CHECK_EQ(unsorted_handlers.size(), std::set<ManifestHandler*>::size_type(0))
       << "Extension manifest handlers have circular dependencies!";
 }
 
 }  // namespace extensions