diff --git a/lib/utils/settings.js b/lib/utils/settings.js
index f67f55fe97..7b858c2284 100644
--- a/lib/utils/settings.js
+++ b/lib/utils/settings.js
@@ -338,4 +338,22 @@ export let legacyNoObservedAttributes =
  */
 export const setLegacyNoObservedAttributes = function(noObservedAttributes) {
   legacyNoObservedAttributes = noObservedAttributes;
-};
\ No newline at end of file
+};
+
+/**
+ * Setting to enable use of `adoptedStyleSheets` for sharing style sheets
+ * between component instances' shadow roots, if the app uses built Shady CSS
+ * styles.
+ */
+export let shareBuiltCSSWithAdoptedStyleSheets =
+  window.Polymer && window.Polymer.shareBuiltCSSWithAdoptedStyleSheets || false;
+
+/**
+ * Sets `shareBuiltCSSWithAdoptedStyleSheets` globally.
+ *
+ * @param {boolean} newValue enable or disable `shareBuiltCSSWithAdoptedStyleSheets`
+ * @return {void}
+ */
+export const setShareBuiltCSSWithAdoptedStyleSheets = function(value) {
+  shareBuiltCSSWithAdoptedStyleSheets = value;
+};