Bug 1794070 - Add "overscrolled" state in APZTestData.additionalData. r=botond

We'd like to use this for testing overscroll state in mochitests. Differential Revision: https://phabricator.services.mozilla.com/D160433
2022-11-21 03:10:05 +00:00 · 2022-11-21 03:10:05 +00:00 · 7ad2ff3232
--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@ -3559,6 +3559,9 @@ bool APZCTreeManager::GetAPZTestData(LayersId aLayersId,
      if (apzc->GetCheckerboardMagnitude(clippedBounds)) {
        apzcState += "checkerboarding,";
      }
+      if (apzc->IsOverscrolled()) {
+        apzcState += "overscrolled,";
+      }
      aOutData->RecordAdditionalData(viewId, apzcState);
    }
  }
--- a/gfx/layers/apz/test/mochitest/helper_overscroll_in_apz_test_data.html
+++ b/gfx/layers/apz/test/mochitest/helper_overscroll_in_apz_test_data.html
@ -0,0 +1,29 @@
+<!DOCTYPE HTML>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, minimum-scale=1.0">
+<title>A simple test checks "overscrolled" info in APZTestData</title>
+<title>Tests scroll anchoring updates in-progress wheel scrolling __relatively__</title>
+<script src="apz_test_utils.js"></script>
+<script src="apz_test_native_event_utils.js"></script>
+<script src="/tests/SimpleTest/paint_listener.js"></script>
+<div style="height: 300vh; background-color: blue;"></div><!-- Make the root scrollable -->
+<script>
+  async function test() {
+    // Try to overscroll by using setAsyncScrollOffset to avoid race conditions
+    // that APZTestData haven't been arrived on the main-thread.
+    SpecialPowers.DOMWindowUtils.setAsyncScrollOffset(document.scrollingElement, 0, -100);
+
+    const scrollId =
+      SpecialPowers.DOMWindowUtils.getViewId(document.scrollingElement);
+    const data = SpecialPowers.DOMWindowUtils.getCompositorAPZTestData();
+    for (apzcData of data.additionalData) {
+      if (apzcData.key == scrollId) {
+        ok(apzcData.value.split(",").includes("overscrolled"));
+      }
+    }
+  }
+
+  waitUntilApzStable()
+  .then(test)
+  .then(subtestDone, subtestFailed);
+</script>
--- a/gfx/layers/apz/test/mochitest/test_group_touchevents-5.html
+++ b/gfx/layers/apz/test/mochitest/test_group_touchevents-5.html
@ -15,7 +15,11 @@ var subtests = [
  {"file": "helper_bug1669625.html", "dp_suppression": false},
  {"file": "helper_touch_drag_root_scrollbar.html", "prefs": [["apz.allow_zooming", true]]},
  {"file": "helper_touch_drag_root_scrollbar.html", "prefs": [["apz.allow_zooming", false]]},
-
+  {"file": "helper_overscroll_in_apz_test_data.html", "prefs": [
+    ["apz.overscroll.enabled", true],
+    ["apz.overscroll.test_async_scroll_offset.enabled", true],
+    ["apz.test.logging_enabled", true],
+  ]},
  // Add new subtests here. If this starts timing out because it's taking too
  // long, create a test_group_touchevents-6.html file. Refer to 1423011#c57
  // for more details.