| <!DOCTYPE html> |
| <script src="../../../../../resources/js-test.js"></script> |
| <style> |
| #scroller { |
| position: absolute; |
| border: 0; |
| left: 100px; |
| top: 200px; |
| width: 300px; |
| height: 300px; |
| } |
| </style> |
| <iframe id="scroller" srcdoc=" |
| <style> |
| div { |
| background: radial-gradient(#aaf, white, #aaf) fixed; |
| background-size: 200px 200px; |
| height: 1000px; |
| width: 1000px; |
| will-change: transform; |
| } |
| body { |
| margin: 0; |
| } |
| </style> |
| <div></div> |
| "></iframe> |
| <script> |
| var jsTestIsAsync = true; |
| var iframeDoc; |
| |
| description("This test verifies that smooth scrolls run on the main thread " + |
| "when there are fixed backgrounds on the page."); |
| |
| // From ScrollAnimatorCompositorCoordinator::RunState. |
| var RUNNING_ON_MAIN_THREAD = "RunningOnMainThread"; |
| function isScrollAnimatingOnMainThread(node) { |
| return internals.getScrollAnimationState(node) == RUNNING_ON_MAIN_THREAD; |
| } |
| |
| onload = function() { |
| if (!window.eventSender || !window.internals) { |
| debug("This test requires window.eventSender.") |
| finishJSTest(); |
| return; |
| } |
| internals.settings.setScrollAnimatorEnabled(true); |
| |
| // Click in the scrollbar. |
| eventSender.mouseMoveTo(390, 300); |
| eventSender.mouseDown(); |
| eventSender.mouseUp(); |
| |
| // EventSender updated the lifecycle to prepaint on mouseUp. |
| // When scrollbars inject scroll gestures, handling the mouse down queues a |
| // gesture scroll update, but the main thread has not yet yielded so there's |
| // nothing to update at this point in time. The queued gesture event will |
| // run once this thread yields - this will register/schedule the animation |
| // and put it in a WaitingForCompositorState until the next compositing |
| // lifecycle phase runs (which happens after rAF on the next frame). |
| // Updating the animation will cause it to recognize that it needs |
| // to run on the main thread and update the state accordingly. |
| // Therefore we need to requestAnimationFrame twice before checking |
| // the scroll animation state. |
| // When scrollbar gestures are not enabled, isScrollAnimatingOnMainThread |
| // will return true in the first rAF callback, so check there as well. |
| requestAnimationFrame(function() { |
| iframeDoc = document.querySelector("#scroller").contentDocument; |
| window.animatedOnMainThread = isScrollAnimatingOnMainThread(iframeDoc); |
| requestAnimationFrame(function() { |
| if (!animatedOnMainThread) { |
| animatedOnMainThread = isScrollAnimatingOnMainThread(iframeDoc); |
| } |
| shouldBeTrue("animatedOnMainThread"); |
| finishJSTest(); |
| }); |
| }); |
| }; |
| |
| </script> |
