[sensors] Dispatch sensor events using postTask

third_party/WebKit/LayoutTests/sensor/resources/sensor-helpers.js

 'use strict';
 
 function sensor_mocks(mojo) {
   return define('Generic Sensor API mocks', [
     'mojo/public/js/core',
     'mojo/public/js/bindings',
     'mojo/public/js/connection',
     'device/generic_sensor/public/interfaces/sensor_provider.mojom',
     'device/generic_sensor/public/interfaces/sensor.mojom',
   ], (core, bindings, connection, sensor_provider, sensor) => {
@@ skipping 176 matching lines @@
         this.shared_buffer_handle_ = rv.handle;
         this.active_sensor_ = null;
         this.get_sensor_should_fail_ = false;
         this.resolve_func_ = null;
         this.is_continuous_ = false;
       }
 
       // Returns initialized Sensor proxy to the client.
       getSensor(type, stub) {
         if (this.get_sensor_should_fail_) {
-          return getSensorResponse(null, null);
+          return getSensorResponse(null,
+              connection.bindProxy(null, sensor.SensorClient));
         }
 
         let offset =
                 (sensor.SensorType.LAST - type) * this.reading_size_in_bytes_;
         let reporting_mode = sensor.ReportingMode.ON_CHANGE;
         if (this.is_continuous_) {
             reporting_mode = sensor.ReportingMode.CONTINUOUS;
         }
 
         if (this.active_sensor_ == null) {
@@ skipping 84 matching lines @@
   });
 }
 
 function sensor_test(func, name, properties) {
   mojo_test(mojo => sensor_mocks(mojo).then(sensor => {
     let result = Promise.resolve(func(sensor));
     let cleanUp = () => { sensor.mockSensorProvider.reset(); };
     return result.then(cleanUp, cleanUp);
   }), name, properties);
 }