Fixed resize event to be fired on the appearance of scroll bar in iframe

Added check for change of scrollable area size in iframe to make resize event fired on the appearance of scroll bar in iframe. And added a test case to wpt. Bug: 1487465 Change-Id: Ida82a010461ac6d856d879842d413bbbe19c67a4 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5096173 Commit-Queue: Nate Chapin <[email protected]> Reviewed-by: David Bokan <[email protected]> Reviewed-by: Nate Chapin <[email protected]> Cr-Commit-Position: refs/heads/main@{#1238373}
Tobias710219 · Dec 16, 2023 · a85f0df · a85f0df
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commit a85f0df
Showing 1 changed file with 41 additions and 0 deletions.
diff --git a/visual-viewport/viewport-scrollbars-cause-resize-in-iframe.html b/visual-viewport/viewport-scrollbars-cause-resize-in-iframe.html
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+<!doctype html>
+<title>Viewport: Scrollbars Cause Resize</title>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, minimum-scale=1">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="viewport_support.js"></script>
+<h1>Viewport: Scrollbars Cause Resize In IFrame</h1>
+<h4>
+    Test Description: This test checks that the appearance of classic
+    scrollbars will cause a resize event to be fired at window.visualViewport in iframe.
+</h4>
+<iframe srcdoc="<p>Hello, world!</p>"></iframe>
+<script>
+  async_test(t => {
+    window.onload = () => {
+      const iframe = document.querySelector("iframe");
+
+      let resize_event_count = 0;
+      iframe.contentWindow.visualViewport.addEventListener("resize", () => {
+        resize_event_count++;
+      });
+
+      const originalVisualViewportWidth = iframe.contentWindow.visualViewport.width;
+
+      iframe.contentDocument.body.style.height = "10000px";
+      // Force layout to queue a resize event at this moment.
+      iframe.contentDocument.body.clientWidth;
+
+      requestAnimationFrame(t.step_func_done(() => {
+        // it's uncontrollable whether the test will run
+        // with classic or overlay scrollbars in the case of Mac,
+        // so the check has to be conditional.
+        const width_changed = iframe.contentWindow.visualViewport.width !== originalVisualViewportWidth;
+        assert_equals(resize_event_count, width_changed ? 1 : 0);
+      }));
+    }
+  }, "the appearance of classic scrollbars will fire a resize event" +
+      "at window.visualViewport in iframe");
+</script>
+<div id="log"></div>