[PPAPI] Fix a bunch of spelling mistakes

ppapi/api/dev/ppb_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>PPB_TextInput_Dev</code> interface.
  */
 
 label Chrome {
@@ skipping 55 matching lines @@
   /**
    * Cancels the current composition in IME.
    */
   void CancelCompositionText([in] PP_Instance instance);
 
   /**
    * In response to the <code>PPP_TextInput_Dev::RequestSurroundingText</code>
    * call, informs the browser about the current text selection and surrounding
    * text. <code>text</code> is a UTF-8 string that contains the current range
    * of text selection in the plugin. <code>caret</code> is the byte-index of
-   * the caret poisition within <code>text</code>. <code>anchor</code> is the
+   * the caret position within <code>text</code>. <code>anchor</code> is the
    * byte-index of the anchor position (i.e., if a range of text is selected,
-   * it is the other edge of selection diffrent from <code>caret</code>. If
+   * it is the other edge of selection different from <code>caret</code>. If
    * there are no selection, <code>anchor</code> is equal to <code>caret</code>.
    *
    * Typical use of this information in the browser is to enable "reconversion"
    * features of IME that puts back the already committed text into the
    * pre-commit composition state. Another use is to improve the precision
    * of suggestion of IME by taking the context into account (e.g., if the caret
-   * looks to be on the begining of a sentense, suggest capital letters in a
+   * looks to be on the beginning of a sentence, suggest capital letters in a
    * virtual keyboard).
    *
    * When the focus is not on text, call this function setting <code>text</code>
    * to an empty string and <code>caret</code> and <code>anchor</code> to zero.
    * Also, the plugin should send the empty text when it does not want to reveal
    * the selection to IME (e.g., when the surrounding text is containing
    * password text).
    */
   [version=0.2]
   void UpdateSurroundingText([in] PP_Instance instance,
                              [in] str_t text,
                              [in] uint32_t caret,
                              [in] uint32_t anchor);
 
   /**
    * Informs the browser when a range of text selection is changed in a plugin.
    * When the browser needs to know the content of the updated selection, it
    * pings back by <code>PPP_TextInput_Dev::RequestSurroundingText</code>. The
    * plugin then should send the information with
    * <code>UpdateSurroundingText</code>.
    */
   [version=0.2]
   void SelectionChanged([in] PP_Instance instance);
 };