refactor add_css_to_component to not save customStyleTag in component.$$

src/compiler/compile/render_dom/index.ts

@@ -44,8 +44,8 @@ export default function dom(
 
 	if (should_add_css) {
 		body.push(b`
-			function ${add_css}(target) {
-				@append_style_if_not_present(target, "${component.stylesheet.id.replace('svelte-', '')}", "${styles}");
+			function ${add_css}(options) {
+				@add_css_to_component(options, "${component.stylesheet.id.replace('svelte-', '')}", "${styles}");
 			}
 		`);
 	}
@@ -529,7 +529,7 @@ export default function dom(
 				constructor(options) {
 					super(${options.dev && 'options'});
 
-					${should_add_css && b`@add_css_to_component(this, ${add_css}, options);`}
+					${should_add_css && b`${add_css}(options);`}
 
 					@init(this, options, ${definition}, ${has_create_fragment ? 'create_fragment' : 'null'}, ${not_equal}, ${prop_indexes}, ${dirty});
 					${options.dev && b`@dispatch_dev("SvelteRegisterComponent", { component: this, tagName: "${name.name}", options, id: create_fragment.name });`}

src/runtime/internal/Component.ts

@@ -1,7 +1,7 @@
 import { add_render_callback, flush, schedule_update, dirty_components } from './scheduler';
 import { current_component, set_current_component } from './lifecycle';
 import { blank_object, is_empty, is_function, run, run_all, noop } from './utils';
-import { children, detach } from './dom';
+import { append, children, detach, element } from './dom';
 import { transition_in } from './transitions';
 
 interface Fragment {
@@ -100,9 +100,20 @@ function make_dirty(component, i) {
 
 let appendStylesTo = document.head;
 
-export function add_css_to_component(add_css, { customStyleTag }) {
+export function add_css_to_component(
+	{ customStyleTag },
+	styleSheetId: string,
+	styles: string,
+	styleId:string = `svelte-${styleSheetId}-style`) {
+
 	if (customStyleTag) appendStylesTo = customStyleTag;
-   add_css(appendStylesTo);
+
+	if (!appendStylesTo.querySelector('#' + styleId)) {
+		const style = element('style');
+		style.id = styleId;
+		style.textContent = styles;
+		append(appendStylesTo, style);
+	}
 }
 
 export function init(component, options, instance, create_fragment, not_equal, props, dirty = [-1]) {

src/runtime/internal/dom.ts

@@ -1,18 +1,5 @@
 import { has_prop } from './utils';
 
-export function append_style_if_not_present(
-	target: Element,
-	styleSheetId: string,
-	styles: string,
-	styleId:string = `svelte-${styleSheetId}-style`) {
-	if (!target.querySelector('#' + styleId)) {
-		const style = element('style');
-		style.id = styleId;
-		style.textContent = styles;
-		append(target, style);
-	}
-}
-
 export function append(target: Node, node: Node) {
 	target.appendChild(node);
 }