Generalize rebase-errors.py so it works for other files.

net/cert/internal/verify_certificate_chain_unittest.cc

 // Copyright 2015 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 "net/cert/internal/verify_certificate_chain.h"
 
 #include "net/cert/internal/signature_policy.h"
 #include "net/cert/internal/trust_store.h"
 #include "net/cert/internal/verify_certificate_chain_typed_unittest.h"
 
 namespace net {
 
 namespace {
 
 class VerifyCertificateChainDelegate {
  public:
   static void Verify(const ParsedCertificateList& chain,
                      const scoped_refptr<TrustAnchor>& trust_anchor,
                      const der::GeneralizedTime& time,
                      bool expected_result,
-                     const std::string& expected_errors) {
+                     const std::string& expected_errors,
+                     const std::string& test_file_path) {
     ASSERT_TRUE(trust_anchor);
 
     SimpleSignaturePolicy signature_policy(1024);
 
     CertErrors errors;
     bool result = VerifyCertificateChain(chain, trust_anchor.get(),
                                          &signature_policy, time, &errors);
     EXPECT_EQ(expected_result, result);
-    EXPECT_EQ(expected_errors, errors.ToDebugString());
+    EXPECT_EQ(expected_errors, errors.ToDebugString()) << "Test file: "
+                                                       << test_file_path;
   }
 };
 
 }  // namespace
 
 INSTANTIATE_TYPED_TEST_CASE_P(VerifyCertificateChain,
                               VerifyCertificateChainSingleRootTest,
                               VerifyCertificateChainDelegate);
 
 }  // namespace net