Add HTTPBodyStream interface, three concrete implementations, and their tests.

util/file/fd_io.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 86 matching lines @@
 void CheckedReadFDAtEOF(int fd) {
   char c;
   ssize_t rv = ReadFD(fd, &c, 1);
   if (rv < 0) {
     PCHECK(rv == 0) << "read";
   } else {
     CHECK_EQ(rv, 0) << "read";
   }
 }
 
+bool LoggingCloseFD(int fd) {
+  int rv = IGNORE_EINTR(close(fd));
+  PLOG_IF(ERROR, rv != 0) << "close";
+  return rv == 0;
+}
+
 }  // namespace crashpad