Remove ENABLE_CUSTOM_ELEMENTS compile time flag

Source/bindings/v8/RuntimeEnabledFeatures.h

Index: Source/bindings/v8/RuntimeEnabledFeatures.h
diff --git a/Source/bindings/v8/RuntimeEnabledFeatures.h b/Source/bindings/v8/RuntimeEnabledFeatures.h
index 9d9209fca17a0d119742a1c43dabf0cfa35e6520..178d0fa466f5b16a890433485719fd40d952961d 100644
--- a/Source/bindings/v8/RuntimeEnabledFeatures.h
+++ b/Source/bindings/v8/RuntimeEnabledFeatures.h
@@ -210,10 +210,8 @@ public:
     static bool authorShadowDOMForAnyElementEnabled() { return isAuthorShadowDOMForAnyElementEnabled; }
     static void setAuthorShadowDOMForAnyElementEnabled(bool isEnabled) { isAuthorShadowDOMForAnyElementEnabled = isEnabled; }
 
-#if ENABLE(CUSTOM_ELEMENTS)
     static bool customDOMElementsEnabled() { return isCustomDOMElementsEnabled; }
     static void setCustomDOMElements(bool isEnabled) { isCustomDOMElementsEnabled = isEnabled; }
-#endif
 
     static bool styleScopedEnabled() { return isStyleScopedEnabled; }
     static void setStyleScopedEnabled(bool isEnabled) { isStyleScopedEnabled = isEnabled; }
@@ -308,9 +306,7 @@ private:
 
     static bool isAuthorShadowDOMForAnyElementEnabled;
 
-#if ENABLE(CUSTOM_ELEMENTS)
     static bool isCustomDOMElementsEnabled;
-#endif
 
     static bool isStyleScopedEnabled;