Move language detection to a component

components/translate/common/translate_constants.h

+// Copyright 2013 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 COMPONENTS_TRANSLATE_COMMON_TRANSLATE_CONSTANTS_H_
+#define COMPONENTS_TRANSLATE_COMMON_TRANSLATE_CONSTANTS_H_
+
+namespace translate {
+
+// The language code used when the language of a page could not be detected.
+// (Matches what the CLD -Compact Language Detection- library reports.)
+extern const char* const kUnknownLanguageCode;
+
+}  // namespace translate
+
+#endif  // COMPONENTS_TRANSLATE_COMMON_TRANSLATE_CONSTANTS_H_