Prevent direct use of "replacement" text encoding.

Source/wtf/text/TextCodecReplacementTest.cpp

 // Copyright 2014 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 "config.h"
 
 #include "wtf/text/TextCodecReplacement.h"
 
 #include "wtf/OwnPtr.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/TextCodec.h"
 #include "wtf/text/TextEncoding.h"
 #include "wtf/text/TextEncodingRegistry.h"
 #include "wtf/text/WTFString.h"
 #include <gtest/gtest.h>
 
 namespace WTF {
 
 namespace {
 
 // Just one example, others are listed in the codec implementation.
 const char* replacementAlias = "iso-2022-kr";
 
 TEST(TextCodecReplacement, Aliases)
 {
-    // FIXME: The 'replacement' label itself should not be referenceable by
-    // resources or script - it's a specification convenience - but much of
-    // the wtf/text API asserts that an encoding name is a label for itself.
-    // crbug.com/277037
+    // "replacement" is not a valid alias for itself
+    EXPECT_FALSE(TextEncoding("replacement").isValid());
+    EXPECT_FALSE(TextEncoding("rEpLaCeMeNt").isValid());
 
     EXPECT_TRUE(TextEncoding(replacementAlias).isValid());
     EXPECT_STREQ("replacement", TextEncoding(replacementAlias).name());
 }
 
 TEST(TextCodecReplacement, DecodesToFFFD)
 {
     TextEncoding encoding(replacementAlias);
     OwnPtr<TextCodec> codec(newTextCodec(encoding));
 
@@ skipping 16 matching lines @@
     const UChar testCase[] = { 0x6F22, 0x5B57 };
     size_t testCaseSize = WTF_ARRAY_LENGTH(testCase);
     CString result = codec->encode(testCase, testCaseSize, QuestionMarksForUnencodables);
 
     EXPECT_STREQ("\xE6\xBC\xA2\xE5\xAD\x97", result.data());
 }
 
 } // namespace
 
 } // namespace WTF