[Sensors] Simplify calculation of the reporting period

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SensorProxy_h
 #define SensorProxy_h
 
 #include "core/dom/ExceptionCode.h"
 #include "core/page/PageVisibilityObserver.h"
 #include "device/generic_sensor/public/cpp/sensor_reading.h"
@@ skipping 20 matching lines @@
   WTF_MAKE_NONCOPYABLE(SensorProxy);
 
  public:
   class Observer : public GarbageCollectedMixin {
    public:
     // Has valid 'Sensor' binding, {add, remove}Configuration()
     // methods can be called.
     virtual void OnSensorInitialized() {}
     // Observer should update its cached reading and send 'onchange'
     // event if needed.
-    // |timestamp| Reference timestamp in seconds of the moment when
-    // sensor reading was updated from the buffer.
-    // Note: |timestamp| values are only used to calculate elapsed time
-    // between shared buffer readings. These values *do not* correspond
-    // to sensor reading timestamps which are obtained on platform side.
-    virtual void OnSensorReadingChanged(double timestamp) {}
+    virtual void OnSensorReadingChanged() {}
     // An error has occurred.
     virtual void OnSensorError(ExceptionCode,
                                const String& sanitized_message,
                                const String& unsanitized_message) {}
   };
 
   ~SensorProxy();
 
   void Dispose();
 
@@ skipping 86 matching lines @@
   using ReadingBuffer = device::SensorReadingSharedBuffer;
   static_assert(
       sizeof(ReadingBuffer) ==
           device::mojom::blink::SensorInitParams::kReadBufferSizeForTests,
       "Check reading buffer size for tests");
 };
 
 }  // namespace blink
 
 #endif  // SensorProxy_h