Added a PolicySchema class.

chrome/browser/policy/policy_schema.h

+// 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.
+
+#ifndef CHROME_BROWSER_POLICY_POLICY_SCHEMA_H_
+#define CHROME_BROWSER_POLICY_POLICY_SCHEMA_H_
+
+#include <map>
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
+
+namespace policy {
+
+// Maps known policy keys to their expected types. Currently, only the top-level
+// type is declared; the types of list and dictionary entries are not declared.

[Mattias Nissler (ping if slow), 2013/05/15 10:04:12]

Is there a plan for further type checks? In particular, can you elaborate on
"currently"? Are there plans or not?

[Joao da Silva, 2013/05/19 13:17:08]

That comment made me think more about this, and I realized that the types of
sub-schemas is also needed to load dictionaries and lists correctly on Windows.

This class has been expanded to represent properties and list items.

+class PolicySchema {
+ public:
+  typedef std::map<std::string, base::Value::Type> TypeMap;
+
+  // Parses |schema| as a JSON v3 schema, and additionally verifies that:
+  // - the version is JSON schema v3;
+  // - the top-level entry is of type "object";
+  // - the top-level object doesn't contain "additionalProperties" nor
+  //   "patternProperties";
+  // - each "property" maps to a schema with one "type";
+  // If all the checks pass then the parsed PolicySchema is returned; otherwise
+  // returns NULL.
+  static scoped_ptr<PolicySchema> Parse(const std::string& schema,
+                                        std::string* error);
+  ~PolicySchema();
+
+  const TypeMap& type_map() const { return type_map_; }
+
+ private:
+  PolicySchema();
+
+  TypeMap type_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(PolicySchema);
+};
+
+}  // namespace policy
+
+#endif  // CHROME_BROWSER_POLICY_POLICY_SCHEMA_H_