[Sensors] Improvements in shared buffer managing

device/generic_sensor/platform_sensor_provider_base.h

Index: device/generic_sensor/platform_sensor_provider_base.h
diff --git a/device/generic_sensor/platform_sensor_provider_base.h b/device/generic_sensor/platform_sensor_provider_base.h
index a64758a6b94d4e216070b39c2c1750b332508a32..af63d1e3c9924b3963d37caeea504f2880ca5f48 100644
--- a/device/generic_sensor/platform_sensor_provider_base.h
+++ b/device/generic_sensor/platform_sensor_provider_base.h
@@ -21,8 +21,6 @@ class PlatformSensorProviderBase : public base::NonThreadSafe {
 
   // Creates new instance of PlatformSensor.
   void CreateSensor(mojom::SensorType type,
-                    uint64_t size,
-                    uint64_t offset,
                     const CreateSensorCallback& callback);
 
   // Gets previously created instance of PlatformSensor by sensor type |type|.
@@ -31,6 +29,9 @@ class PlatformSensorProviderBase : public base::NonThreadSafe {
   // Shared buffer getters.
   mojo::ScopedSharedBufferHandle CloneSharedBufferHandle();
 
+  // Gets shared buffer offset for the given sensor type.
+  uint64_t GetSharedBufferOffset(mojom::SensorType type);
+
  protected:
   PlatformSensorProviderBase();
   virtual ~PlatformSensorProviderBase();
@@ -38,7 +39,6 @@ class PlatformSensorProviderBase : public base::NonThreadSafe {
   // Method that must be implemented by platform specific classes.
   virtual void CreateSensorInternal(mojom::SensorType type,
                                     mojo::ScopedSharedBufferMapping mapping,
-                                    uint64_t buffer_size,
                                     const CreateSensorCallback& callback) = 0;
 
  private: