Fix file descriptor ownership.

Previously, we attempt to pass ownership of the fd owned by a
ParcelFileDescriptor to a FileInputStream, which explodes when we try to
close it.

Bug: http://b/156867945
Bug: http://b/159264419
Test: treehugger
Change-Id: I9d5124658beb50f0a08499ed09e652037cb9ae66
(cherry picked from commit 3e29e4a39c)

services/backup/java/com/android/server/backup/restore/FullRestoreEngineThread.java

@@ -1,10 +1,10 @@
 package com.android.server.backup.restore;
 
 import android.os.ParcelFileDescriptor;
+import android.os.ParcelFileDescriptor.AutoCloseInputStream;
 
 import libcore.io.IoUtils;
 
-import java.io.FileInputStream;
 import java.io.InputStream;
 
 class FullRestoreEngineThread implements Runnable {
@@ -19,7 +19,7 @@ class FullRestoreEngineThread implements Runnable {
         // We *do* want this FileInputStream to own the underlying fd, so that
         // when we are finished with it, it closes this end of the pipe in a way
         // that signals its other end.
-        mEngineStream = new FileInputStream(engineSocket.getFileDescriptor(), true);
+        mEngineStream = new AutoCloseInputStream(engineSocket);
         // Tell it to be sure to leave the agent instance up after finishing
         mMustKillAgent = false;
     }