Snap layers in views to physical pixel

ui/compositor/debug_utils.cc

Index: ui/compositor/debug_utils.cc
diff --git a/ui/compositor/debug_utils.cc b/ui/compositor/debug_utils.cc
index 37b9af42f306b44bed4613c09be20c20f0fac1f0..462cfc965f3a0f972f93d4de927f32c3dc43799c 100644
--- a/ui/compositor/debug_utils.cc
+++ b/ui/compositor/debug_utils.cc
@@ -64,6 +64,17 @@ void PrintLayerHierarchyImp(const Layer* layer,
   *out << L'\n' << UTF8ToWide(property_indent_str);
   *out << L"bounds: " << layer->bounds().x() << L',' << layer->bounds().y();
   *out << L' ' << layer->bounds().width() << L'x' << layer->bounds().height();
+  if (!layer->subpixel_position_offset().IsZero())
+    *out << " " << UTF8ToWide(layer->subpixel_position_offset().ToString());
+
+  const ui::Layer* mask = const_cast<ui::Layer*>(layer)->layer_mask_layer();
+
+  if (mask) {
+    *out << L'\n' << UTF8ToWide(property_indent_str);
+    *out << L"mask layer: " << std::setprecision(2)
+         << UTF8ToWide(mask->bounds().ToString())
+         << UTF8ToWide(mask->subpixel_position_offset().ToString());
+  }
 
   if (layer->opacity() != 1.0f) {
     *out << L'\n' << UTF8ToWide(property_indent_str);