Adding Android Binder Bridge (abb) utility launched from adbd.

Once launched, abb will listen for incoming Binder cli requests.
Executing in-process provides 6x latency improvement (125ms vs 25ms on
PixelXL) for commands like 'package path'

Intended usage by Android Studio for fast deployment and patching of APKs.

Test: manual
BUG: 111621042

Change-Id: Ica84eb2ec9628efa441ecd627b119f3361feaf9f
diff --git a/adb_io.h b/adb_io.h
index aa550af..2ccaa32 100644
--- a/adb_io.h
+++ b/adb_io.h
@@ -21,6 +21,8 @@
 
 #include <string>
 
+#include "adb_unique_fd.h"
+
 // Sends the protocol "OKAY" message.
 bool SendOkay(int fd);
 
@@ -73,4 +75,12 @@
 // Same as above, but formats the string to send.
 bool WriteFdFmt(int fd, const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3)));
 
+#if !ADB_HOST
+// Sends an FD via Unix domain socket.
+bool SendFileDescriptor(int socket_fd, int fd);
+
+// Receives an FD via Unix domain socket.
+bool ReceiveFileDescriptor(int socket_fd, unique_fd* fd, std::string* error);
+#endif
+
 #endif /* ADB_IO_H */