Add unittests for certificate and file parsing.

net/tools/transport_security_state_generator/spki_hash.cc

 // 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.
 
 #include "net/tools/transport_security_state_generator/spki_hash.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "third_party/boringssl/src/include/openssl/sha.h"
 
 namespace net {
 
 namespace transport_security_state {
 
 SPKIHash::SPKIHash() {}
 
 SPKIHash::~SPKIHash() {}
 
-bool SPKIHash::FromString(const std::string& hash_string) {
-  std::string base64_string;
+bool SPKIHash::FromString(base::StringPiece hash_string) {
+  base::StringPiece base64_string;
 
   if (!base::StartsWith(hash_string, "sha256/",
                         base::CompareCase::INSENSITIVE_ASCII)) {
     return false;
   }
   base64_string = hash_string.substr(7);
 
   std::string decoded;
   if (!base::Base64Decode(base64_string, &decoded)) {
     return false;
   }
 
   if (decoded.size() != size()) {
     return false;
   }
 
   memcpy(data_, decoded.data(), decoded.size());
   return true;
 }
 
 void SPKIHash::CalculateFromBytes(const uint8_t* input, size_t input_length) {
   SHA256(input, input_length, data_);
 }
 
 }  // namespace transport_security_state
 
 }  // namespace net