gfx::Transform API clean-up

ui/compositor/layer.cc

Index: ui/compositor/layer.cc
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index e05372c26faf45b50cbe45894b0459658e65888f..725e382577753ab415777a69a402d17b1512c9bd 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -615,10 +615,13 @@ bool Layer::GetTransformRelativeTo(const Layer* ancestor,
                                    gfx::Transform* transform) const {
   const Layer* p = this;
   for (; p && p != ancestor; p = p->parent()) {
+    gfx::Transform translation;
+    translation.Translate(static_cast<float>(p->bounds().x()),
+                          static_cast<float>(p->bounds().y()));
     if (p->transform().HasChange())
-      transform->ConcatTransform(p->transform());
-    transform->ConcatTranslate(static_cast<float>(p->bounds().x()),
-                               static_cast<float>(p->bounds().y()));
+      *transform = translation * p->transform() * *transform;
+    else
+      *transform = translation * *transform;
   }
   return p == ancestor;
 }
@@ -781,7 +784,9 @@ void Layer::RecomputeTransform() {
                             0, 1.0f / device_scale_factor_, 0,
                             0, 0, 1);
   transform.ConcatTransform(transform_);
-  transform.ConcatTranslate(bounds_.x(), bounds_.y());
+  gfx::Transform translate;
+  translate.Translate(bounds_.x(), bounds_.y());
+  transform.ConcatTransform(translate);
   transform.ConcatTransform(scale_translate);
   web_layer_->setTransform(transform.matrix());
 }