[Sensors] Implement bindings for AbsoluteOrientationSensor

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

 // 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.
 
 #include "modules/sensor/SensorProxy.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/sensor/SensorProviderProxy.h"
 #include "modules/sensor/SensorReadingUpdater.h"
@@ skipping 111 matching lines @@
   int readAttempts = 0;
   const int kMaxReadAttemptsCount = 10;
   device::SensorReading readingData;
   while (!tryReadFromBuffer(readingData)) {
     if (++readAttempts == kMaxReadAttemptsCount) {
       handleSensorError();
       return;
     }
   }
 
-  m_reading = readingData;
+  if (m_reading.timestamp != readingData.timestamp) {
+    m_reading = readingData;
+    for (Observer* observer : m_observers)

[haraken, 2017/03/27 09:59:38]

Don't you need to copy the observers before starting iterating it? See line 142.

[Mikhail, 2017/03/27 10:04:01]

This callback will not cause invokes of JS handlers so `m_observers` container
won't be modified in the middle. So this is safe.

+      observer->onSensorReadingChanged();
+  }
 }
 
 void SensorProxy::notifySensorChanged(double timestamp) {
   // This notification leads to sync 'onchange' event sending, so
   // we must cache m_observers as it can be modified within event handlers.
   auto copy = m_observers;
   for (Observer* observer : copy)
-    observer->onSensorReadingChanged(timestamp);
+    observer->notifySensorChanged(timestamp);
 }
 
 void SensorProxy::RaiseError() {
   handleSensorError();
 }
 
 void SensorProxy::SensorReadingChanged() {
   DCHECK_EQ(ReportingMode::ON_CHANGE, m_mode);
   if (isActive())
     m_readingUpdater->start();
@@ skipping 116 matching lines @@
   const device::OneWriterSeqLock& seqlock = buffer->seqlock.value();
   auto version = seqlock.ReadBegin();
   auto readingData = buffer->reading;
   if (seqlock.ReadRetry(version))
     return false;
   result = readingData;
   return true;
 }
 
 }  // namespace blink