Make a new test to enforce the sizes of all structs and enums in the C API....

ppapi/c/pp_size.h

 // Copyright (c) 2010 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.
 
 #ifndef PPAPI_C_PP_SIZE_H_
 #define PPAPI_C_PP_SIZE_H_
 
 /**
  * @file
  * Defines the API ...
  *
  * @addtogroup PP
  * @{
  */
 
 #include "ppapi/c/pp_macros.h"
 #include "ppapi/c/pp_stdint.h"
 
 struct PP_Size {
   int32_t width;
   int32_t height;
 };
+PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_Size, 8);
 
 PP_INLINE struct PP_Size PP_MakeSize(int32_t w, int32_t h) {
   struct PP_Size ret;
   ret.width = w;
   ret.height = h;
   return ret;
 }
 
 /**
  * @}
  * End addtogroup PP
  */
 #endif  // PPAPI_C_PP_SIZE_H_