Fix handling of wrapped processes [part 1].

Change 3fe595108f changed our pipe creation to CLOEXEC,
which doesn't work so well for wrapper processes that call exec.

Sending down the PID pre-exec won't work so well because wrappers
are arbitrary and might fork themselves before finally starting
the child application process.

Change-Id: I065f0f2150dc1ff04d2b2e8b25f06b4c754809b9

core/java/com/android/internal/os/ZygoteConnection.java

@@ -16,6 +16,7 @@
 
 package com.android.internal.os;
 
+import static android.system.OsConstants.F_SETFD;
 import static android.system.OsConstants.O_CLOEXEC;
 import static android.system.OsConstants.STDERR_FILENO;
 import static android.system.OsConstants.STDIN_FILENO;
@@ -194,6 +195,7 @@ class ZygoteConnection {
                 FileDescriptor[] pipeFds = Os.pipe2(O_CLOEXEC);
                 childPipeFd = pipeFds[1];
                 serverPipeFd = pipeFds[0];
+                Os.fcntlInt(childPipeFd, F_SETFD, 0);
             }
 
             /**