RenderDocument: Fix pointerevent_touch-adjustment_click_target.html.

The test is failing on headless tests with RenderDocument enabled. This
is happening because the initial navigation causes a RFH swap that then
results in a synthetic mouse move event being fired (that does not
happen if the RFH is not swapped). This synthetic mouse event happens
before the page is loaded (i.e. before the "load" event is fired). This
CL fixes the test by waiting for the "load" event before adding the
various event listeners for the touch/pointer events.

Bug: 432385247, 40615943
Change-Id: I22d23ebf2063cb488146b2ee8ae784079cf42dad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6824135
Commit-Queue: Liam Brady <[email protected]>
Reviewed-by: Alex Moshchuk <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1498358}

Author: blu25

pointerevents/pointerevent_touch-adjustment_click_target.html

@@ -26,16 +26,13 @@
         .send();
 }
 
-
-addEventListener('load', () => {
-  input_gesture = inject_input();
-});
-
-async_test(t => {
+promise_test(async t => {
     const link = document.getElementById('link');
     const expectedEventLog = ['pointerdown-link', 'touchstart-link', 'pointerup-link', 'touchend-link', 'click-link'];
     const eventLogRecorder = [];
 
+    await new Promise(resolve => addEventListener("load", resolve));
+
     const eventNames = ['touchstart', 'touchmove', 'touchend', 'pointerdown', 'pointermove', 'pointerup', 'click'];
     for (eventName of eventNames) {
         document.addEventListener(eventName, t.step_func(event => {
@@ -63,5 +60,6 @@
             }
         }));
     }
+    input_gesture = inject_input();
 });
 </script>