[Sensors] Implement sensor data polling

third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.h

Index: third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.h
diff --git a/third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.h b/third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.h
index 086a132794de74bf69e7f2eaaf79d1d5cd8737bb..c396d21f717744341e5b52363060acce091629b4 100644
--- a/third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.h
+++ b/third_party/WebKit/Source/modules/sensor/SensorPollingStrategy.h
@@ -27,6 +27,11 @@ public:
     virtual void stopPolling() = 0;
 
     virtual ~SensorPollingStrategy() {}
+
+protected:
+    SensorPollingStrategy(double frequency, std::unique_ptr<Function<void()>>);
+    double m_frequency;
+    std::unique_ptr<Function<void()>> m_pollFunc;
 };
 
 } // namespace blink