Add a compatibility symbol for the MemoryBase constructor.

Third-party libraries are currently trying to use the
MemoryBase constructor but failing because we fixed the
definition of ssize_t. This is a stop-gap for users of
this private API until we can get them fixed.

Bug: 8253769
Change-Id: I8a19770f3252d88ee87023fde625cc6289924b0d
diff --git a/include/binder/MemoryBase.h b/include/binder/MemoryBase.h
index 463e26d..fa0b8d1 100644
--- a/include/binder/MemoryBase.h
+++ b/include/binder/MemoryBase.h
@@ -40,6 +40,9 @@
     const sp<IMemoryHeap>& getHeap() const { return mHeap; }
 
 private:
+    // Backwards compatibility for libdatabase_sqlcipher (http://b/8253769).
+    MemoryBase(const sp<IMemoryHeap>& heap, long offset, unsigned int size);
+
     size_t          mSize;
     ssize_t         mOffset;
     sp<IMemoryHeap> mHeap;