[sensors] Fix flakiness in generic sensors 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();
@@ skipping 258 matching lines @@
 
       // Binds object to mojo message pipe
       bindToPipe(pipe) {
         this.stub_ = connection.bindHandleToStub(
             pipe, sensor_provider.SensorProvider);
         bindings.StubBindings(this.stub_).delegate = this;
       }
 
       // Mock functions
 
+      // Resets mock sensor provider stub bindings.
+      resetSensorProvider() {
+        this.reset();
+        bindings.StubBindings(this.stub_).close();
+      }
+
       // Resets state of mock SensorProvider between test runs.
       reset() {
         if (this.active_sensor_ != null) {
           this.active_sensor_.reset();
           this.active_sensor_ = null;
         }
 
         this.get_sensor_should_fail_ = false;
         this.resolve_func_ = null;
         this.max_frequency_ = 60;
@@ skipping 51 matching lines @@
     };
 
     let onFailure = () => {
       sensor.mockSensorProvider.reset();
       return new Promise((resolve, reject) => { setTimeout(reject, 0); });
     };
 
     return Promise.resolve(func(sensor)).then(onSuccess, onFailure);
   }), name, properties);
 }
+
+function resetSensorProvider() {
+  sensor_test(sensor => {
+    sensor.mockSensorProvider.resetSensorProvider();
+    return Promise.resolve();
+  }, 'Reset sensor provider proxy.');
+}