Add GetSequenceNumber function to PPB_Flash_Clipboard

ppapi/api/private/ppb_flash_clipboard.idl

 /* 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.
  */
 
 /**
  * This file defines the private <code>PPB_Flash_Clipboard</code> API used by
  * Pepper Flash for reading and writing to the clipboard.
  */
 
 label Chrome {
   M19 = 4.0,
-  M24 = 5.0
+  M24 = 5.0,
+  M34 = 5.1
 };
 
 /**
  * This enumeration contains the types of clipboards that can be accessed.
  * These types correspond to clipboard types in WebKit.
  */
 [assert_size(4)]
 enum PP_Flash_Clipboard_Type {
   /** The standard clipboard. */
   PP_FLASH_CLIPBOARD_TYPE_STANDARD = 0,
@@ skipping 111 matching lines @@
    * too large to be written, <code>PP_ERROR_BADARGUMENT</code> if a PP_Var
    * cannot be converted into the format supplied or <code>PP_FAILED</code>
    * if the format is not supported.
    */
   [version=5.0]
   int32_t WriteData([in] PP_Instance instance_id,
       [in] PP_Flash_Clipboard_Type clipboard_type,
       [in] uint32_t data_item_count,
       [in, size_is(data_item_count)] uint32_t[] formats,
       [in, size_is(data_item_count)] PP_Var[] data_items);
+
+  /**
+   * Returns a sequence number which uniquely identifies clipboard state. This

[teravest, 2014/01/21 14:31:55]

Nit: This doesn't actually return the sequence number. I'd replace "returns"
with "gets", but this is pretty minor.

[raymes, 2014/01/22 23:23:18]

Done.

+   * can be used to version the data on the clipboard and determine whether
+   * it has changed. The sequence number will be placed in |sequence_number| and
+   * PP_TRUE returned if the sequence number was retrieved successfully.
+   */
+  [version=5.1]
+  PP_Bool GetSequenceNumber([in] PP_Instance instance_id,
+                            [in] PP_Flash_Clipboard_Type clipboard_type,
+                            [out] uint64_t sequence_number);
 };