Revert "Revert "SharedMemory: break Cleaner reference cycle.""

This reverts commit b16411f83aee0847fec77d79fb4e98b2e3fa8828.

The original change was correct, and the revert re-introduced an
FD leak.

Test: make
Bug: 197500807
Change-Id: Id5118e2b21fa4b7a7198edfe9541f755fd581752
diff --git a/core/java/android/os/SharedMemory.java b/core/java/android/os/SharedMemory.java
index 46eb2ec..20c672a 100644
--- a/core/java/android/os/SharedMemory.java
+++ b/core/java/android/os/SharedMemory.java
@@ -63,7 +63,7 @@
 
         mMemoryRegistration = new MemoryRegistration(mSize);
         mCleaner = Cleaner.create(mFileDescriptor,
-                new Closer(mFileDescriptor, mMemoryRegistration));
+                new Closer(mFileDescriptor.getInt$(), mMemoryRegistration));
     }
 
     /**
@@ -325,10 +325,10 @@
      * Cleaner that closes the FD
      */
     private static final class Closer implements Runnable {
-        private FileDescriptor mFd;
+        private int mFd;
         private MemoryRegistration mMemoryReference;
 
-        private Closer(FileDescriptor fd, MemoryRegistration memoryReference) {
+        private Closer(int fd, MemoryRegistration memoryReference) {
             mFd = fd;
             mMemoryReference = memoryReference;
         }
@@ -336,7 +336,9 @@
         @Override
         public void run() {
             try {
-                Os.close(mFd);
+                FileDescriptor fd = new FileDescriptor();
+                fd.setInt$(mFd);
+                Os.close(fd);
             } catch (ErrnoException e) { /* swallow error */ }
             mMemoryReference.release();
             mMemoryReference = null;