[Sensors] Reland: Align sensor reading updates and 'onchange' notification with rAF.

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

Index: third_party/WebKit/LayoutTests/sensor/resources/sensor-helpers.js
diff --git a/third_party/WebKit/LayoutTests/sensor/resources/sensor-helpers.js b/third_party/WebKit/LayoutTests/sensor/resources/sensor-helpers.js
index 03f32d9418ec51e827ddf52841cb44a74f8de4da..1225458173fdaddd59fc9c06a0af4ea64684937d 100644
--- a/third_party/WebKit/LayoutTests/sensor/resources/sensor-helpers.js
+++ b/third_party/WebKit/LayoutTests/sensor/resources/sensor-helpers.js
@@ -39,6 +39,7 @@ function sensor_mocks(mojo) {
         this.reporting_mode_ = reportingMode;
         this.sensor_reading_timer_id_ = null;
         this.update_reading_function_ = null;
+        this.reading_updates_count_ = 0;
         this.suspend_called_ = null;
         this.resume_called_ = null;
         this.add_configuration_called_ = null;
@@ -62,6 +63,9 @@ function sensor_mocks(mojo) {
         return Promise.resolve({frequency: 5});
       }
 
+      reading_updates_count() {
+        return this.reading_updates_count_;
+      }
       // Adds configuration for the sensor and starts reporting fake data
       // through update_reading_function_ callback.
       addConfiguration(configuration) {
@@ -197,9 +201,12 @@ function sensor_mocks(mojo) {
               this.active_sensor_configurations_[0].frequency;
           let timeout = (1 / max_frequency_used) * 1000;
           this.sensor_reading_timer_id_ = window.setInterval(() => {

[shalamov, 2016/12/21 10:41:03]

Should we clear previous interval if addConfiguration called multiple times?
e.g. when there are two active JS sensor objects?

[Mikhail, 2016/12/21 13:06:28]

Right, thanks for the catch!

-            if (this.update_reading_function_)
+            if (this.update_reading_function_) {
               this.update_reading_function_(this.buffer_,
-                                            this.expects_modified_reading_);
+                                            this.expects_modified_reading_,
+                                            this.reading_updates_count_);
+              this.reading_updates_count_++;
+            }
             if (this.reporting_mode_ === sensor.ReportingMode.ON_CHANGE) {
               this.client_.sensorReadingChanged();
             }