Chrome Version: 73.0.3675.0

What steps will reproduce the problem?
(1) Run chrome with --enable-gpu-benchmarking
(2) Visit csreis.github.io/tests/cross-site-iframe-simple.html
(3) Run the following in the iframe's javascript context

var x = 300; var y = 300;
var pointerActions =
            [{source: "touch",
              actions: [
                { name: "pointerDown", x: x, y: y },
                { name: "pointerMove", x: x, y: y - 20 },
                { name: "pointerMove", x: x, y: y - 40 },
                { name: "pointerMove", x: x, y: y - 60 },
                { name: "pointerMove", x: x, y: y - 100 },
                { name: "pointerUp" }]}];
chrome.gpuBenchmarking.pointerActionSequence(pointerActions);

What is the expected result?
The frame should scroll, as it would if --disable-site-isolation-trials were used.

What happens instead?
The frame does not scroll and we reach SyntheticGestureTargetBase::DispatchWebTouchEventToPlatform.


Furthermore, some gestures have a check in the renderer whether the coordinates are within the view, and the child renderer thinks the view is 0x0. So,

chrome.gpuBenchmarking.pinchBy(2.0, 100, 100, undefined, undefined, chrome.gpuBenchmarking.MOUSE_INPUT)

produces the error "Anchor point not in bounds"