fix Surface positions are not floats

Added Surface.setPosition(float, float) which allows to set a surface's
position in float.

Bug: 5239859
Change-Id: I903aef4ad5b5999142202fb8ea30fe216d805711
diff --git a/services/surfaceflinger/Transform.h b/services/surfaceflinger/Transform.h
index 8fa5b86..ec74243 100644
--- a/services/surfaceflinger/Transform.h
+++ b/services/surfaceflinger/Transform.h
@@ -64,8 +64,8 @@
             uint32_t    getOrientation() const;
 
             float const* operator [] (int i) const;  // returns column i
-            int     tx() const;
-            int     ty() const;
+            float   tx() const;
+            float   ty() const;
 
             // modify the transform
             void        reset();