Update shelf spacing in Chrome OS according to the MD specs

ash/test/shelf_view_test_api.cc

Index: ash/test/shelf_view_test_api.cc
diff --git a/ash/test/shelf_view_test_api.cc b/ash/test/shelf_view_test_api.cc
index 53ef6c78195cdd7473e9dff31dc8ccc0c572bd7f..fe3d894750ffd5a04a3ec9c81a5620687ec07702 100644
--- a/ash/test/shelf_view_test_api.cc
+++ b/ash/test/shelf_view_test_api.cc
@@ -111,11 +111,11 @@ gfx::Size ShelfViewTestAPI::GetPreferredSize() {
 }
 
 int ShelfViewTestAPI::GetButtonSize() {
-  return kShelfButtonSize;
+  return GetShelfLayoutConstant(SHELF_BUTTON_SIZE);
 }
 
 int ShelfViewTestAPI::GetButtonSpacing() {
-  return kShelfButtonSpacing;
+  return GetShelfLayoutConstant(SHELF_BUTTON_SPACING);
 }
 
 void ShelfViewTestAPI::ButtonPressed(views::Button* sender,