Make the Vector copy constructor for mismatched inline sizes explicit.

Source/core/scripts/templates/StylePropertyShorthand.cpp.tmpl

Index: Source/core/scripts/templates/StylePropertyShorthand.cpp.tmpl
diff --git a/Source/core/scripts/templates/StylePropertyShorthand.cpp.tmpl b/Source/core/scripts/templates/StylePropertyShorthand.cpp.tmpl
index a491e03c0ad856c194d92b4328bffc89e886faa8..de699376ffd09427f693f79115bfc97f4b9be41c 100644
--- a/Source/core/scripts/templates/StylePropertyShorthand.cpp.tmpl
+++ b/Source/core/scripts/templates/StylePropertyShorthand.cpp.tmpl
@@ -74,7 +74,9 @@ const Vector<StylePropertyShorthand> matchingShorthandsForLonghand(CSSPropertyID
         {% for shorthand in shorthands -%}
             {{ longhand_id }}Shorthands.uncheckedAppend({{ shorthand.camel_case_name }}Shorthand());
         {% endfor -%}
-        map.set({{ longhand_id }}, {{ longhand_id }}Shorthands);
+        // FIXME: the explicit Vector conversion copies into a temporary and is
+        // wasteful.
+        map.set({{ longhand_id }}, Vector<StylePropertyShorthand>({{ longhand_id }}Shorthands));
 {%- endfor %}
     }
     return map.get(propertyID);