[PPAPI] Fix a bunch of spelling mistakes

ppapi/api/dev/ppp_text_input_dev.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 <code>PPP_TextInput_Dev</code> interface.
  */
 
 label Chrome {
   M19 = 0.1
 };
 
 /**
  * <code>PPP_TextInput_Dev</code> is a set of function pointers that the
  * plugin has to implement to provide hints for text input system (IME).
  */
 interface PPP_TextInput_Dev {
   /**
-   * Requests the plugin to send back the text arround the current caret or
+   * Requests the plugin to send back the text around the current caret or
    * selection by <code>PPB_TextInput_Dev::UpdateSurroundingText</code>.
    * It is recommended to include the <code>desired_number_of_characters</code>
    * characters before and after the selection, but not mandatory.
    */
   void RequestSurroundingText([in] PP_Instance instance,
                               [in] uint32_t desired_number_of_characters);
 };