Update HDCP for external displays

So the secure flag of Display object in Display Manager (DM) can
be set correctly. HWC calls the onSync method as a workaround,
to notify SurfaceFlinger (SF) about hdcp changes, SF in turn sends
an event to DM, DM will then fetch and update display info.

Bug: 280818362
Test: manual
Change-Id: I29ce0337865b51c0fc7bf7c2d7fdd4cd6d66ef46
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index ac390cb..97b56a2 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -95,6 +95,7 @@
     // isSecure indicates whether this display can be trusted to display
     // secure surfaces.
     bool isSecure() const;
+    void setSecure(bool secure);
 
     int getWidth() const;
     int getHeight() const;