Add URL generator / json parser for getting start_page_token of changes.

google_apis/drive/drive_api_parser.h

 // 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.
 
 #ifndef GOOGLE_APIS_DRIVE_DRIVE_API_PARSER_H_
 #define GOOGLE_APIS_DRIVE_DRIVE_API_PARSER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 946 matching lines @@
   // Return false if parsing fails.
   bool Parse(const base::Value& value);
 
   GURL next_link_;
   int64_t largest_change_id_;
   std::vector<std::unique_ptr<ChangeResource>> items_;
 
   DISALLOW_COPY_AND_ASSIGN(ChangeList);
 };
 
+// StartPageToken is the starting pageToken for listing future changes.
+// https://developers.google.com/drive/v2/reference/changes/getStartPageToken
+class StartPageToken {
+ public:
+  StartPageToken();
+  ~StartPageToken();
+
+  // Registers the mapping between JSON field names and the members in this
+  // class.
+  static void RegisterJSONConverter(
+      base::JSONValueConverter<StartPageToken>* converter);
+
+  // Returns true if the |value| has kind field for StartPageToken.
+  static bool HasStartPageTokenKind(const base::Value& value);
+
+  // Creates an instance from parsed JSON.
+  static std::unique_ptr<StartPageToken> CreateFrom(const base::Value& value);
+
+  // Returns the starting page token for listing future changes.
+  const std::string& start_page_token() const { return start_page_token_; }
+
+  void set_start_page_token(const std::string& start_page_token) {
+    start_page_token_ = start_page_token;
+  }
+
+ private:
+  friend class DriveAPIParserTest;
+  FRIEND_TEST_ALL_PREFIXES(DriveAPIParserTest, StartPageTokenParser);
+
+  // Parses and initializes data members from content of |value|.
+  // Return false if parsing fails.
+  bool Parse(const base::Value& value);
+
+  std::string start_page_token_;
+
+  DISALLOW_COPY_AND_ASSIGN(StartPageToken);
+};
+
 }  // namespace google_apis
 
 #endif  // GOOGLE_APIS_DRIVE_DRIVE_API_PARSER_H_