[Sensors] Improve error logging in sensors layout tests

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

 'use strict';
 
 // Wraps callback and calls reject_func if callback throws an error.
 class CallbackWrapper {
   constructor(callback, reject_func) {
     this.wrapper_func_ = (args) => {
       try {
         callback(args);
       } catch(e) {
-        reject_func();
+        reject_func(e);
       }
     }
   }
 
   get callback() {
     return this.wrapper_func_;
   }
 }
 
 function sensor_mocks(mojo) {
@@ skipping 346 matching lines @@
 function sensor_test(func, name, properties) {
   mojo_test(mojo => sensor_mocks(mojo).then(sensor => {
     // Clean up and reset mock sensor stubs asynchronously, so that the blink
     // side closes its proxies and notifies JS sensor objects before new test is
     // started.
     let onSuccess = () => {
       sensor.mockSensorProvider.reset();
       return new Promise((resolve, reject) => { setTimeout(resolve, 0); });
     };
 
-    let onFailure = () => {
+    let onFailure = error => {
       sensor.mockSensorProvider.reset();
-      return new Promise((resolve, reject) => { setTimeout(reject, 0); });
+      return new Promise((resolve, reject) => { setTimeout(() => {reject(error);}, 0); });
     };
 
     return Promise.resolve(func(sensor)).then(onSuccess, onFailure);
   }), name, properties);
 }