Bug 1394228 - Intermittent test_touch_action.html test timed out. r=kats.

Wait for chrome process to handle all synthesize requests and then finish the test.

MozReview-Commit-ID: 2qiFEO6l7wN

dom/events/test/pointerevents/touch_action_helpers.js

@@ -5,6 +5,15 @@ function touchActionSetup(testDriver) {
   document.body.addEventListener('touchend', testDriver, { passive: true });
 }
 
+function touchActionSetupAndWaitTestDone(testDriver) {
+  let testDone = new Promise(resolve => {
+    add_completion_callback(resolve);
+  });
+
+  document.body.addEventListener('touchend', testDriver, { passive: true });
+  return testDone;
+}
+
 function touchScrollRight(aSelector = '#target0', aX = 20, aY = 20) {
   var target = document.querySelector(aSelector);
   return ok(synthesizeNativeTouchDrag(target, aX + 40, aY, -40, 0), "Synthesized horizontal drag");
@@ -35,11 +44,13 @@ function waitForResetScrollLeft(aSelector = '#target0') {
 // The main body functions to simulate the input events required for the named test
 
 function* pointerevent_touch_action_auto_css_touch_manual(testDriver) {
-  touchActionSetup(testDriver);
+  let testDone = touchActionSetupAndWaitTestDone(testDriver);
 
   yield touchScrollRight();
   yield waitForApzFlushedRepaints(testDriver);
   yield touchScrollDown();
+  yield testDone.then(testDriver);
+  subtestDone();
 }
 
 function* pointerevent_touch_action_button_test_touch_manual(testDriver) {
@@ -103,11 +114,13 @@ function* pointerevent_touch_action_inherit_child_pan_x_child_pan_y_touch_manual
 }
 
 function* pointerevent_touch_action_inherit_highest_parent_none_touch_manual(testDriver) {
-  touchActionSetup(testDriver);
+  let testDone = touchActionSetupAndWaitTestDone(testDriver);
 
   yield touchScrollDown('#target0 > div');
   yield waitForApzFlushedRepaints(testDriver);
   yield touchScrollRight('#target0 > div');
+  yield testDone.then(testDriver);
+  subtestDone();
 }
 
 function* pointerevent_touch_action_inherit_parent_none_touch_manual(testDriver) {
@@ -151,11 +164,13 @@ function* pointerevent_touch_action_pan_x_pan_y_pan_y_touch_manual(testDriver) {
 }
 
 function* pointerevent_touch_action_pan_x_pan_y_touch_manual(testDriver) {
-  touchActionSetup(testDriver);
+  let testDone = touchActionSetupAndWaitTestDone(testDriver);
 
   yield touchScrollDown();
   yield waitForApzFlushedRepaints(testDriver);
   yield touchScrollRight();
+  yield testDone.then(testDriver);
+  subtestDone();
 }
 
 function* pointerevent_touch_action_pan_y_css_touch_manual(testDriver) {