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

ppapi/tests/all_c_sizes.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.
+ *
+ * This header ensures (at compile time) that each type has the expected size.
+ * The purpose is to ensure that the ABI of PPAPI is known, consistent, and
+ * stable.  If the size of one of these types changes, then it is necessary to
+ * change the version of any interfaces that rely on the changed type(s).
+ *
+ * Note that the ABI only consists of the headers under ppapi/c.  But they may
+ * be compiled by either a C or C++ compiler, so we want to make sure they are
+ * consistent regardless of whether a C or C++ compiler is used.  See
+ * test_struct_sizes_c.c and test_struct_sizes_cpp.cc for more information.
+ */
+
+#ifndef PPAPI_TESTS_ALL_C_SIZES_H_
+#define PPAPI_TESTS_ALL_C_SIZES_H_
+
+#include "ppapi/tests/all_c_includes.h"
+
+#if !defined(__native_client__) && (defined(_M_X64) || defined(__x86_64__))
+/* These sizes are for 64-bit compilation on Windows, Mac, and Linux.  Native
+   client follows ILP32 even if -m64 is used.  This means pointers are always
+   4 bytes in native client, and it matches Win32  (see below).
+
+   Each of these structs uses at least one type which differs in size or
+   alignment between 64-bit and 32-bit (e.g. pointers, int64_t, uint64_t,
+   or double), and they are not padded to keep their size consistent.  */
+#include "ppapi/tests/all_sizes_64.h"
+#else
+/* This section is for compilation on 32-bit targets plus native client (in both
+   32-bit and 64-bit mode, since native client always conforms to ILP32).
+
+   These types all contain pointers and have no types that are 8-byte aligned on
+   Windows/NaCl.  The pointers cause the sizes to differ between 32-bit and
+   64-bit, but the lack of 8-byte-aligned types allows them to be consistent
+   between Windows 32-bit, Native Client, and Mac/Linux 32-bit. */
+#include "ppapi/tests/all_sizes_32.h"
+#endif
+
+#endif  // PPAPI_TESTS_ALL_C_SIZES_H_
+