Add a PPB_Find_Private function to set the tickmarks on the page.

ppapi/api/private/ppb_find_private.idl

 /* Copyright 2014 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 <code>PPB_Find_Private</code> interface.
  */
 
 [generate_thunk]
@@ skipping 35 matching lines @@
       [in] PP_Instance instance,
       [in] int32_t total,
       [in] PP_Bool final_result);
 
   /**
    * Updates the index of the currently selected search item.
    */
   void SelectedFindResultChanged(
       [in] PP_Instance instance,
       [in] int32_t index);
+
+  /**
+   * Updates the tickmarks on the scrollbar for the find request. |tickmarks|
+   * contains |count| PP_Rects indicating the tickmark ranges.
+   */
+  void SetTickmarks(
+      [in] PP_Instance instance,
+      [in, size_as=count] PP_Rect[] tickmarks,
+      [in] uint32_t count);
 };