Fix transform hints

The hints were being set a little too late, so the pre-rotation stuff
wasn't quite working.

Bug 7054997

Change-Id: Id8d5c626db7a76f768ba762a145b315878ee08e6
diff --git a/services/surfaceflinger/LayerBase.h b/services/surfaceflinger/LayerBase.h
index 4651517..7326f53 100644
--- a/services/surfaceflinger/LayerBase.h
+++ b/services/surfaceflinger/LayerBase.h
@@ -229,6 +229,12 @@
      */
     virtual void onPostComposition() { }
 
+    /**
+     * Updates the SurfaceTexture's transform hint, for layers that have
+     * a SurfaceTexture.
+     */
+    virtual void updateTransformHint() const { }
+
     /** always call base class first */
     virtual void dump(String8& result, char* scratch, size_t size) const;
     virtual void shortDump(String8& result, char* scratch, size_t size) const;