Fix some types at the IPC layer. Sizes should be unsigned.

ppapi/api/dev/pp_video_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.
  */
 
 /**
  * NOTE: these must be kept in sync with the versions in media/!
  */
 
 
@@ skipping 35 matching lines @@
 
   /**
    * Buffer to hold the bitstream data. Should be allocated using the
    * PPB_Buffer interface for consistent interprocess behaviour.
    */
   PP_Resource data;
 
   /**
    * Size of the bitstream contained in buffer (in bytes).
    */
-  int32_t size;
+  uint32_t size;
 };
 
 /**
  * Struct for specifying texture-backed picture data.
  */
 [assert_size(16)]
 struct PP_PictureBuffer_Dev {
   /**
    * Client-specified id for the picture buffer. By using this value client can
    * keep track of the buffers it has assigned to the video decoder and how they
@@ skipping 50 matching lines @@
    */
   PP_VIDEODECODERERROR_UNREADABLE_INPUT = 3,
 
   /** 
    * A failure occurred at the browser layer or lower.  Examples of such
    * failures include GPU hardware failures, GPU driver failures, GPU library
    * failures, browser programming errors, and so on.
    */
   PP_VIDEODECODERERROR_PLATFORM_FAILURE = 4
 };