Revert "Revert "Add a way to turn off unique_fd's operator int.""

The original commit broke aosp-master-with-phones, because of
vendor libraries the depended on the int versions of libbase functions.

This patch reverts the revert, and also adds ABI-compatibility shims for
the replaced functions.

This reverts commit dfdf916d09f6583d3fd1db1e33c79ed60bff2480.

Bug: http://b/131312539
Test: treehugger
Test: forrest run of aosp-master-with-phones
Change-Id: I75cc84ec8d963e20862f7662e8e2f409471f41cc
diff --git a/shell_service_protocol.cpp b/shell_service_protocol.cpp
index 13b66ec..95afaff 100644
--- a/shell_service_protocol.cpp
+++ b/shell_service_protocol.cpp
@@ -22,7 +22,7 @@
 
 #include "adb_io.h"
 
-ShellProtocol::ShellProtocol(int fd) : fd_(fd) {
+ShellProtocol::ShellProtocol(borrowed_fd fd) : fd_(fd) {
     buffer_[0] = kIdInvalid;
 }