OMX: allow only secure codec to remotely call allocateBuffer.

Bug: 24310423
Change-Id: Iebcfc58b447f925ec2134898060af2ef227266a3
diff --git a/include/media/IOMX.h b/include/media/IOMX.h
index 3d29e4a..27ad694 100644
--- a/include/media/IOMX.h
+++ b/include/media/IOMX.h
@@ -249,6 +249,12 @@
     virtual status_t onTransact(
             uint32_t code, const Parcel &data, Parcel *reply,
             uint32_t flags = 0);
+
+protected:
+    // check if the codec is secure.
+    virtual bool isSecure(IOMX::node_id node) {
+        return false;
+    }
 };
 
 class BnOMXObserver : public BnInterface<IOMXObserver> {