[Sensors] Handle default sensor configuration

device/generic_sensor/public/interfaces/sensor_provider.mojom

 // 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.
 
 module device.mojom;
 
 import "sensor.mojom";
 
-struct SensorReadBuffer {
+struct SensorInitParams {
   // The shared memory handle used to fetch the sensor reading.
   handle<shared_buffer> memory;
 
   // The offset at which shared buffer must be mapped.
-  uint64 offset;
+  uint64 buffer_offset;
 
   // The ReportingMode supported by the sensor.
   ReportingMode mode;
 
+  // Default sensor configuration.
+  SensorConfiguration default_configuration;

[timvolodine, 2016/09/12 16:37:08]

curious how this is described in spec: does the platform decide on default
parameters when the user does not specify them?

[Mikhail, 2016/09/12 17:08:10]

That is not mentioned explicitly, however IMO it is natural to let platform to
define the default parameters so that they fit better to the underlying platform
and hardware

[timvolodine, 2016/09/13 13:17:10]

sounds reasonable.. would you mind raising an issue on the spec github so that
the editors incorporate this at some stage (or at least know about this) ?

+
   // Note: Each sensor's read buffer contains 4 tightly packed 64-bit floating
   // point fields, its layout is: { double timestamp; double values[3] }.
   // So it has a fixed size 4*8 = 32 bytes.
   const uint64 kReadBufferSize = 32;
 };
 
 interface SensorProvider {
   // Gets the sensor interface by the given type.
   //
   // |type| type of the sensor.
   //
   // |sensor_request| the Sensor interface instance to be initialized.
   //
-  // |read_buffer| on success will contain the SensorReadBuffer describing the
-  //               sensor reading buffer details,
+  // |init_params| on success will contain the SensorInitParams describing the
+  //               sensor details,
   //               contains null on failure.
   // |client_request| on success contains a request to be bound by the client,
   //                  contains null on failure.
   GetSensor(SensorType type, Sensor& sensor_request) => (
-      SensorReadBuffer? read_buffer,
+      SensorInitParams? init_params,
       SensorClient&? client_request);
 };