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

util/file/fd_io.h

Index: util/file/fd_io.h
diff --git a/util/file/fd_io.h b/util/file/fd_io.h
index 14481c93752c6fcec8e25566f37c5ea484017341..909e0d92e5896acd75d82770ba9c56fdf3583f43 100644
--- a/util/file/fd_io.h
+++ b/util/file/fd_io.h
@@ -79,6 +79,12 @@ void CheckedWriteFD(int fd, const void* buffer, size_t size);
 //! \sa ReadFD
 void CheckedReadFDAtEOF(int fd);
 
+//! \brief Wraps `close()`, logging an error if the operation fails.
+//!
+//! \return On success, `true` is returned. On failure, an error is logged and
+//!     `false` is returned.
+bool LoggingCloseFD(int fd);
+
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_FILE_FD_IO_H_