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

ppapi/c/dev/ppb_char_set_dev.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_DEV_PPB_CHAR_SET_DEV_H_
 #define PPAPI_C_DEV_PPB_CHAR_SET_DEV_H_
 
 #include "ppapi/c/pp_module.h"
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/pp_var.h"
@@ skipping 13 matching lines @@
   // errors will be removed from the output.
   PP_CHARSET_CONVERSIONERROR_SKIP,
 
   // Replaces the error or unrepresentable character with a substitution
   // character. When converting to a Unicode character set (UTF-8 or UTF-16)
   // it will use the unicode "substitution character" U+FFFD. When converting
   // to another character set, the character will be charset-specific. For
   // many languages this will be the representation of the '?' character.
   PP_CHARSET_CONVERSIONERROR_SUBSTITUTE
 };
+PP_COMPILE_ASSERT_ENUM_SIZE_IN_BYTES(PP_CharSet_ConversionError, 4);
 
 struct PPB_CharSet_Dev {
   // Converts the UTF-16 string pointed to in |*utf16| to an 8-bit string in the
   // specified code page. |utf16_len| is measured in UTF-16 units, not bytes.
   // This value may not be NULL.
   //
   // The return value is a NULL-terminated 8-bit string corresponding to the
   // new character set, or NULL on failure. THIS STRING MUST BE FREED USING
   // PPB_Core::MemFree(). The length of the returned string, not including the
   // terminating NULL, will be placed into *output_length. When there is no
@@ skipping 25 matching lines @@
   // Returns a string var representing the current multi-byte character set of
   // the current system.
   //
   // WARNING: You really shouldn't be using this function unless you're dealing
   // with legacy data. You should be using UTF-8 or UTF-16 and you don't have
   // to worry about the character sets.
   struct PP_Var (*GetDefaultCharSet)(PP_Module module);
 };
 
 #endif  // PPAPI_C_DEV_PPB_CHAR_SET_DEV_H_