Ignore unknown attributes when parsing JSON schemas.

components/policy/core/common/schema.cc

 // Copyright 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 "components/policy/core/common/schema.h"
 
 #include <algorithm>
 #include <map>
 #include <utility>
 #include <vector>
@@ skipping 482 matching lines @@
       if (!*it || !GetItems().Validate(**it))
         return false;
     }
   }
 
   return true;
 }
 
 // static
 Schema Schema::Parse(const std::string& content, std::string* error) {
-  // Validate as a generic JSON schema.
+  // Validate as a generic JSON schema, and ignore unknown attributes; they
+  // may become used in a future version of the schema format.
   scoped_ptr<base::DictionaryValue> dict =
-      JSONSchemaValidator::IsValidSchema(content, error);
+      JSONSchemaValidator::IsValidSchema(content, false, error);
   if (!dict)
     return Schema();
 
   // Validate the main type.
   std::string string_value;
   if (!dict->GetString(schema::kType, &string_value) ||
       string_value != schema::kObject) {
     *error =
         "The main schema must have a type attribute with \"object\" value.";
     return Schema();
@@ skipping 61 matching lines @@
 
 Schema Schema::GetItems() const {
   CHECK(valid());
   CHECK_EQ(base::Value::TYPE_LIST, type());
   if (node_->extra == kInvalid)
     return Schema();
   return Schema(storage_, storage_->schema(node_->extra));
 }
 
 }  // namespace policy