fix(window_state_context.js): prevent restoring if already minimized. (…

…web-platform-tests#39802)

page-visibility/resources/window_state_context.js

@@ -1,37 +1,45 @@
 function window_state_context(t) {
-    let rect = null;
-    let state = "restored";
-    t.add_cleanup(async () => {
-        if (state === "minimized")
-            await restore();
-    });
-    async function restore() {
-        state = "restored";
-        await test_driver.set_window_rect(rect);
+  let rect = null;
+  let state = "restored";
+  t.add_cleanup(async () => {
+    if (state === "minimized") {
+      await restore();
     }
-
-    async function minimize() {
-        state = "minimized";
-        rect = await test_driver.minimize_window();
+  });
+  async function restore() {
+    if (state !== "minimized") {
+      return;
     }
+    state = "restoring";
+    await test_driver.set_window_rect(rect);
+    state = "restored";
+  }
 
-    function visibilityEventPromise() {
-      return new Promise(resolve => new PerformanceObserver(
-        (entries, observer) => { observer.disconnect(); resolve(); }).observe(
-          {type: "visibility-state"}))
-    }
+  async function minimize() {
+    state = "minimized";
+    rect = await test_driver.minimize_window();
+  }
 
-    async function minimizeAndWait() {
-      const promise = visibilityEventPromise();
-      await Promise.all([minimize(), promise]);
-      await new Promise(resolve => t.step_timeout(resolve, 0));
-    }
+  function visibilityEventPromise() {
+    return new Promise((resolve) =>
+      new PerformanceObserver((entries, observer) => {
+        observer.disconnect();
+        resolve();
+      }).observe({ type: "visibility-state" })
+    );
+  }
 
-    async function restoreAndWait() {
-      const promise = visibilityEventPromise();
-      await Promise.all([restore(), promise]);
-      await new Promise(resolve => t.step_timeout(resolve, 0));
-    }
+  async function minimizeAndWait() {
+    const promise = visibilityEventPromise();
+    await Promise.all([minimize(), promise]);
+    await new Promise((resolve) => t.step_timeout(resolve, 0));
+  }
+
+  async function restoreAndWait() {
+    const promise = visibilityEventPromise();
+    await Promise.all([restore(), promise]);
+    await new Promise((resolve) => t.step_timeout(resolve, 0));
+  }
 
-    return {minimize, restore, minimizeAndWait, restoreAndWait};
+  return { minimize, restore, minimizeAndWait, restoreAndWait };
 }