[PPAPI] Fix a bunch of spelling mistakes

ppapi/api/trusted/ppb_browser_font_trusted.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_BrowserFont_Trusted</code> interface.
  */
 label Chrome {
   M19 = 1.0
@@ skipping 184 matching lines @@
    * Draws the text to the image buffer.
    *
    * The given point represents the baseline of the left edge of the font,
    * regardless of whether it is left-to-right or right-to-left (in the case of
    * RTL text, this will actually represent the logical end of the text).
    *
    * The clip is optional and may be NULL. In this case, the text will be
    * clipped to the image.
    *
    * The image_data_is_opaque flag indicates whether subpixel antialiasing can
-   * be performend, if it is supported. When the image below the text is
+   * be performed, if it is supported. When the image below the text is
    * opaque, subpixel antialiasing is supported and you should set this to
    * PP_TRUE to pick up the user's default preferences. If your plugin is
    * partially transparent, then subpixel antialiasing is not possible and
    * grayscale antialiasing will be used instead (assuming the user has
    * antialiasing enabled at all).
    */
   PP_Bool DrawTextAt(
       [in] PP_Resource font,
       [in] PP_Resource image_data,
       [in] PP_BrowserFont_Trusted_TextRun text,
@@ skipping 36 matching lines @@
    * placed at the given position. This handles complex scripts such as Arabic,
    * where characters may be combined or replaced depending on context. Returns
    * -1 on error.
    */
   int32_t PixelOffsetForCharacter(
       [in] PP_Resource font,
       [in] PP_BrowserFont_Trusted_TextRun text,
       [in] uint32_t char_offset);
 };