app: add ability to override settings for autoPreview

src/components/ContentWrap.jsx

@@ -194,8 +194,14 @@ export default class ContentWrap extends Component {
 	 * @param {boolean} isManual Is this a manual preview request from user?
 	 */
 	setPreviewContent(isForced, isManual) {
-		if (!this.props.prefs.autoPreview && !isManual) {
+		if (!isManual) {
-			return;
+			let autoPreview =
+				window.forcedSettings.autoPreview !== undefined
+					? window.forcedSettings.autoPreview
+					: this.props.prefs.autoPreview;
+			if (!autoPreview) {
+				return;
+			}
 		}
 
 		if (!this.props.prefs.preserveConsoleLogs) {

src/components/ContentWrapFiles.jsx

@@ -293,8 +293,14 @@ export default class ContentWrapFiles extends Component {
 	 * @param {boolean} isManual Is this a manual preview request from user?
 	 */
 	setPreviewContent(isForced, isManual) {
-		if (!this.props.prefs.autoPreview && !isManual) {
+		if (!isManual) {
-			return;
+			let autoPreview =
+				window.forcedSettings.autoPreview !== undefined
+					? window.forcedSettings.autoPreview
+					: this.props.prefs.autoPreview;
+			if (!autoPreview) {
+				return;
+			}
 		}
 
 		if (!this.props.prefs.preserveConsoleLogs) {

src/components/app.jsx

@@ -963,7 +963,11 @@ export default class App extends Component {
 
 		const prefs = this.state.prefs;
 		// Show/hide RUN button based on autoPreview setting.
-		runBtn.classList[prefs.autoPreview ? 'add' : 'remove']('hide');
+		let autoPreview =
+			window.forcedSettings.autoPreview !== undefined
+				? window.forcedSettings
+				: prefs.autoPreview;
+		runBtn.classList[autoPreview ? 'add' : 'remove']('hide');
 
 		this.contentWrap.applyCodemirrorSettings(this.state.prefs);