Add a .gitattributes file to force LF line-endings in net/http/*.pins files.

net/tools/transport_security_state_generator/input_file_parsers.cc

 // Copyright 2017 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/input_file_parsers.h"
 
 #include <sstream>
 #include <vector>
 
 #include "base/json/json_reader.h"
@@ skipping 149 matching lines @@
 enum class CertificateParserState {
   PRE_NAME,
   POST_NAME,
   IN_CERTIFICATE,
   IN_PUBLIC_KEY
 };
 
 }  // namespace
 
 bool ParseCertificatesFile(base::StringPiece certs_input, Pinsets* pinsets) {
+  if (certs_input.find("\r\n") != base::StringPiece::npos) {
+    LOG(ERROR) << "CRLF line-endings found in the pins file. All files must "
+                  "use LF (unix style) line-endings.";
+    return false;
+  }
+
   std::string line;
   CertificateParserState current_state = CertificateParserState::PRE_NAME;
 
   const base::CompareCase& compare_mode = base::CompareCase::INSENSITIVE_ASCII;
   std::string name;
   std::string buffer;
   std::string subject_name;
   bssl::UniquePtr<X509> certificate;
   SPKIHash hash;
 
@@ skipping 188 matching lines @@
 
     pinsets->RegisterPinset(std::move(pinset));
   }
 
   return true;
 }
 
 }  // namespace transport_security_state
 
 }  // namespace net