Move Cast certificate verification code from extensions to components.

extensions/common/cast/cast_cert_validator_test_helpers.h

-// Copyright 2016 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 EXTENSIONS_COMMON_CAST_CAST_CERT_VALIDATOR_TEST_HELPERS_H_
-#define EXTENSIONS_COMMON_CAST_CAST_CERT_VALIDATOR_TEST_HELPERS_H_
-
-#include <string>
-#include <vector>
-
-#include "base/strings/string_piece.h"
-
-namespace cast_test_helpers {
-
-// Reads a PEM file containing certificates to a vector of their DER data.
-// |file_name| should be relative to //src/extensions/test/data/
-std::vector<std::string> ReadCertificateChainFromFile(
-    const base::StringPiece& file_name);
-
-// Helper structure that describes a message and its various signatures.
-struct SignatureTestData {
-  std::string message;
-
-  // RSASSA PKCS#1 v1.5 with SHA1.
-  std::string signature_sha1;
-
-  // RSASSA PKCS#1 v1.5 with SHA256.
-  std::string signature_sha256;
-};
-
-// Reads a PEM file that contains "MESSAGE", "SIGNATURE SHA1" and
-// "SIGNATURE SHA256" blocks.
-// |file_name| should be relative to //src/extensions/test/data/
-SignatureTestData ReadSignatureTestData(const base::StringPiece& file_name);
-
-}  // namespace cast_test_helpers
-
-#endif  // EXTENSIONS_COMMON_CAST_CAST_CERT_VALIDATOR_TEST_HELPERS_H_