Don't allow '\0' characters in FilePath.

ipc/ipc_message_utils_unittest.cc

 // 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.
 
 #include "base/file_path.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_message_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace IPC {
@@ skipping 35 matching lines @@
 
   // Try reading past the ends for both messages and make sure it fails.
   IPC::Message dummy;
   ASSERT_FALSE(ParamTraits<Message>::Read(&outer_msg, &iter, &dummy));
   ASSERT_FALSE(ParamTraits<int>::Read(&nested_msg, &nested_iter,
                                       &result_content));
 }
 
 // Tests that detection of various bad parameters is working correctly.
 TEST(IPCMessageUtilsTest, ParameterValidation) {
-  IPC::Message message;
   FilePath::StringType okString(FILE_PATH_LITERAL("hello"), 5);
   FilePath::StringType badString(FILE_PATH_LITERAL("hel\0o"), 5);
-  FilePath okPath(okString);
-  FilePath badPath(badString);
-  ParamTraits<FilePath>::Write(&message, okPath);
-  ParamTraits<FilePath>::Write(&message, badPath);
+
+  // Change this if ParamTraits<FilePath>::Write() changes.
+  IPC::Message message;
+  ParamTraits<FilePath::StringType>::Write(&message, okString);
+  ParamTraits<FilePath::StringType>::Write(&message, badString);
 
   PickleIterator iter(message);
+  FilePath okPath;
+  FilePath badPath;
   ASSERT_TRUE(ParamTraits<FilePath>::Read(&message, &iter, &okPath));
   ASSERT_FALSE(ParamTraits<FilePath>::Read(&message, &iter, &badPath));
 }
 
 }  // namespace IPC