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 f8c0754c2aa9ae0cd6d4c2d976af25c9737a60f1..d6dd01267840da8d6c783e7b5bc02f5f20647433 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 GetShelfConstant(SHELF_BUTTON_SIZE);
 }
 
 int ShelfViewTestAPI::GetButtonSpacing() {
-  return kShelfButtonSpacing;
+  return GetShelfConstant(SHELF_BUTTON_SPACING);
 }
 
 void ShelfViewTestAPI::ButtonPressed(views::Button* sender,