Include libbase headers in libbinder include path

We will eventually switch to using libbase's unique_fd in favor of
ScopedFd.  Include the header by itself to check that all build targets
that need libbinder headers are picking up libbase as well.

Bug:  27804373
Test: Compiles

Change-Id: I2920b3d1a5357d81a54267febac3ab72fee88eb1
diff --git a/include/binder/Parcel.h b/include/binder/Parcel.h
index 9c3877e..7ca5d8b 100644
--- a/include/binder/Parcel.h
+++ b/include/binder/Parcel.h
@@ -20,6 +20,7 @@
 #include <string>
 #include <vector>
 
+#include <android-base/unique_fd.h>
 #include <cutils/native_handle.h>
 #include <nativehelper/ScopedFd.h>
 #include <utils/Errors.h>