hwc: Add binder interface to get the visibleRegion

- This binder interface can be used by clients to know the
  active visible region for a display(pri/ext/virt)
- When external orientation is used, return the destFrame of
  the FrameBuffer layer, as its the viewFrame

Change-Id: I7cfd149c76c16b9a3031103c89b1932d44bcbecd
diff --git a/libqdutils/display_config.h b/libqdutils/display_config.h
index c7d8ce9..29edbef 100644
--- a/libqdutils/display_config.h
+++ b/libqdutils/display_config.h
@@ -29,6 +29,7 @@
 #include <gralloc_priv.h>
 #include <qdMetaData.h>
 #include <mdp_version.h>
+#include <hardware/hwcomposer.h>
 
 // This header is for clients to use to set/get global display configuration
 // The functions in this header run in the client process and wherever necessary
@@ -69,4 +70,7 @@
 // Returns 0 on success, negative values on errors
 int setHSIC(int dpy, const HSICData_t& hsic_data);
 
+// get the active visible region for the display
+// Returns 0 on success, negative values on errors
+int getDisplayVisibleRegion(int dpy, hwc_rect_t &rect);
 }; //namespace