sensors: Drop tests for Sensor.start()/stop() return types.

These tests were essentially verifying IDL compliance for some methods,
which is not very relevant in this context.

Change-Id: Ib103418bf03b8843eda90ae291dceb224cf9e4a2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2398918
Commit-Queue: Reilly Grant <[email protected]>
Auto-Submit: Raphael Kubo da Costa <[email protected]>
Reviewed-by: Reilly Grant <[email protected]>
Cr-Commit-Position: refs/heads/master@{#805545}

generic-sensor/generic-sensor-tests.js

@@ -283,17 +283,6 @@ function runGenericSensorTests(sensorName,
   }, `${sensorName}: Test that sensor can be successfully created and its\
  states are correct.`);
 
-  sensor_test(async t => {
-    assert_implements(sensorName in self, `${sensorName} is not supported.`);
-    const sensor = new sensorType();
-    const sensorWatcher = new EventWatcher(t, sensor, ["activate", "error"]);
-    const start_return = sensor.start();
-
-    await sensorWatcher.wait_for("activate");
-    assert_equals(start_return, undefined);
-    sensor.stop();
-  }, `${sensorName}: sensor.start() returns undefined.`);
-
   sensor_test(async t => {
     assert_implements(sensorName in self, `${sensorName} is not supported.`);
     const sensor = new sensorType();
@@ -307,17 +296,6 @@ function runGenericSensorTests(sensorName,
   }, `${sensorName}: no exception is thrown when calling start() on already\
  started sensor.`);
 
-  sensor_test(async t => {
-    assert_implements(sensorName in self, `${sensorName} is not supported.`);
-    const sensor = new sensorType();
-    const sensorWatcher = new EventWatcher(t, sensor, ["activate", "error"]);
-    sensor.start();
-
-    await sensorWatcher.wait_for("activate");
-    const stop_return = sensor.stop();
-    assert_equals(stop_return, undefined);
-  }, `${sensorName}: sensor.stop() returns undefined.`);
-
   sensor_test(async t => {
     assert_implements(sensorName in self, `${sensorName} is not supported.`);
     const sensor = new sensorType();