[sensors] Fix flakiness in generic sensors tests

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 01d06e0fe49538031a917f765795d7a909ac734a..bc955df349d57709f80265e1bf241f8171cebbff 100644
--- a/third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js
+++ b/third_party/WebKit/LayoutTests/sensor/resources/generic-sensor-tests.js
@@ -17,7 +17,6 @@ function runGenericSensorTests(sensorType, updateReading, verifyReading) {
     return new Promise((resolve, reject) => {
       let wrapper = new CallbackWrapper(event => {
         assert_equals(sensorObject.state, 'errored');
-        console.log(event.error.message);
         assert_equals(event.error.name, 'NotFoundError');
         sensorObject.onerror = null;
         resolve();
@@ -195,12 +194,13 @@ function runGenericSensorTests(sensorType, updateReading, verifyReading) {
         })
         .then(mockSensor => {
           return new Promise((resolve, reject) => {
-            sensorObject.onchange = () => {
-              if (verifyReading(sensorObject.reading)) {
-                resolve(mockSensor);
-              }
-            }
-          sensorObject.onerror = reject;
+            let wrapper = new CallbackWrapper(() => {
+              assert_true(verifyReading(sensorObject.reading));
+              resolve(mockSensor);
+            }, reject);
+
+            sensorObject.onchange = wrapper.callback;
+            sensorObject.onerror = reject;
           });
         })
         .then(mockSensor => {