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

ppapi/c/dev/ppb_file_chooser_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_FILE_CHOOSER_DEV_H_
 #define PPAPI_C_DEV_PPB_FILE_CHOOSER_DEV_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
 
 struct PP_CompletionCallback;
 
 typedef enum {
   PP_FILECHOOSERMODE_OPEN,
   PP_FILECHOOSERMODE_OPENMULTIPLE
   // TODO(darin): Should there be a way to choose a directory?
 } PP_FileChooserMode_Dev;
+PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_FileChooserMode_Dev, 4);
 
 struct PP_FileChooserOptions_Dev {
   PP_FileChooserMode_Dev mode;
 
   // A comma-separated list of MIME types such as audio/*,text/plain.  The
   // dialog may restrict selectable files to the specified MIME types.
   // TODO(darin): What if the mime type is unknown to the system?  The plugin
   // may wish to describe the mime type and provide a matching file extension.
   // It is more webby to use mime types here instead of file extensions.
   const char* accept_mime_types;
@@ skipping 27 matching lines @@
   // chosen files.  It should be called in a loop until it returns 0.
   // Depending on the PP_ChooseFileMode requested when the FileChooser was
   // created, the file refs will either be readable or writable.  Their file
   // system type will be PP_FileSystemType_External.  If the user chose no
   // files or cancelled the dialog, then this method will simply return 0
   // the first time it is called.
   PP_Resource (*GetNextChosenFile)(PP_Resource chooser);
 };
 
 #endif  // PPAPI_C_DEV_PPB_FILE_CHOOSER_DEV_H_