Revert of [sensors] Ambient light sensor bindings implementation

third_party/WebKit/Source/modules/sensor/SensorReading.cpp

Index: third_party/WebKit/Source/modules/sensor/SensorReading.cpp
diff --git a/third_party/WebKit/Source/modules/sensor/SensorReading.cpp b/third_party/WebKit/Source/modules/sensor/SensorReading.cpp
index 061711983e3da38fbe6c470411a3aa26362b08e7..12c14881bc9af7be3a74f93e364ea500abd8c641 100644
--- a/third_party/WebKit/Source/modules/sensor/SensorReading.cpp
+++ b/third_party/WebKit/Source/modules/sensor/SensorReading.cpp
@@ -14,6 +14,7 @@
 SensorReading::SensorReading(SensorProxy* sensorProxy)
     : m_sensorProxy(sensorProxy)
 {
+    DCHECK(m_sensorProxy);
 }
 
 DEFINE_TRACE(SensorReading)
@@ -30,15 +31,6 @@
     Performance* performance = DOMWindowPerformance::performance(*window);
     DCHECK(performance);
 
-    if (!m_sensorProxy) {
-        // In cases when SensorReading derived classes are constructed from JS
-        // side, e.g. to create syntetic SensorReadingEvent for testing
-        // purposes, |m_sensorProxy| will be null and SensorReading.timeStamp
-        // would return current DOMHighResTimeStamp, while reading value should
-        // be provided by derived classes.
-        return performance->now();
-    }
-
     return performance->monotonicTimeToDOMHighResTimeStamp(m_sensorProxy->reading().timestamp);
 }