[Sensors] Align sensor reading updates and 'onchange' notification with rAF.

third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js

Index: third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js
diff --git a/third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js b/third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js
index ee5f312333cceab119156d79549531e72f380954..52d878d21b22f559e103853e9c8c7a3575ff5eb2 100644
--- a/third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js
+++ b/third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js
@@ -304,7 +304,10 @@ function runGenericSensorTests(sensorType, updateReading, verifyReading) {
                 // By the moment slow sensor (9 Hz) is notified for the
                 // next time, the fast sensor (30 Hz) has been notified
                 // for int(30/9) = 3 times.
-                assert_equals(fastSensorNotifiedCounter, 3);
+                // In actual implementation updates are bound to rAF,
+                // (not to a timer) sometimes fast sensor gets invoked 4 times.
+                assert_true(fastSensorNotifiedCounter == 3 ||
+                            fastSensorNotifiedCounter == 4);

[foolip, 2016/12/19 13:23:47]

Shouldn't this change have caused the number of update events to decrease only?

A useful test for this change would be a 100 Hz sensor, and verifying that at
most one event is fired per animation frame, if that's the intended behavior.

                 fastSensor.stop();
                 slowSensor.stop();
                 resolve(mockSensor);