[Sensors] Improvements in shared buffer managing

device/generic_sensor/platform_sensor_android.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 DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_ANDROID_H_
 #define DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_ANDROID_H_
 
 #include "device/generic_sensor/platform_sensor.h"
 #include "base/android/scoped_java_ref.h"
 #include "base/memory/ref_counted.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace device {
 
 class PlatformSensorAndroid : public PlatformSensor {
  public:
   // Register C++ methods exposed to Java using JNI.
   static bool RegisterJNI(JNIEnv* env);
 
   PlatformSensorAndroid(mojom::SensorType type,
                         mojo::ScopedSharedBufferMapping mapping,
-                        uint64_t buffer_size,
                         PlatformSensorProvider* provider,
+                        scoped_refptr<base::SingleThreadTaskRunner> task_runner,
                         const base::android::JavaRef<jobject>& java_sensor);
 
   mojom::ReportingMode GetReportingMode() override;
   PlatformSensorConfiguration GetDefaultConfiguration() override;
 
-  void NotifyPlatformSensorReadingChanged(
-      JNIEnv*,
-      const base::android::JavaRef<jobject>& caller);
   void NotifyPlatformSensorError(JNIEnv*,
                                  const base::android::JavaRef<jobject>& caller);
 
+  void UpdatePlatformSensorReading(
+      JNIEnv*,
+      const base::android::JavaRef<jobject>& caller,
+      jdouble timestamp,
+      jdouble value1,
+      jdouble value2,
+      jdouble value3);
+
  protected:
   ~PlatformSensorAndroid() override;
   bool StartSensor(const PlatformSensorConfiguration& configuration) override;
   void StopSensor() override;
   bool CheckSensorConfiguration(
       const PlatformSensorConfiguration& configuration) override;
 
  private:
   // Java object org.chromium.device.sensors.PlatformSensor
   base::android::ScopedJavaGlobalRef<jobject> j_object_;
-  // Task runner that is used by mojo objects for the IPC. Android sensor
-  // objects share separate handler thread that processes sensor
-  // events. Notifications from Java side are forwarded to |task_runner_|.
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   DISALLOW_COPY_AND_ASSIGN(PlatformSensorAndroid);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_ANDROID_H_