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.cpp b/services/surfaceflinger/Transform.cpp
index 05b7527..ba345ce 100644
--- a/services/surfaceflinger/Transform.cpp
+++ b/services/surfaceflinger/Transform.cpp
@@ -91,12 +91,12 @@
     return type() > TRANSLATE;
 }
 
-int Transform::tx() const {
-    return floorf(mMatrix[2][0] + 0.5f);
+float Transform::tx() const {
+    return mMatrix[2][0];
 }
 
-int Transform::ty() const {
-    return floorf(mMatrix[2][1] + 0.5f);
+float Transform::ty() const {
+    return mMatrix[2][1];
 }
 
 void Transform::reset() {
@@ -239,7 +239,9 @@
             out.set(transform(reg.bounds()));
         }
     } else {
-        out = reg.translate(tx(), ty());
+        int xpos = floorf(tx() + 0.5f);
+        int ypos = floorf(ty() + 0.5f);
+        out = reg.translate(xpos, ypos);
     }
     return out;
 }