[sensors] Introduce Generic Sensor API interfaces

device/sensors/public/interfaces/sensor_struct_traits.cc

+// 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 "device/sensors/public/interfaces/sensor_struct_traits.h"
+
+#define CHECK_ENUM(VALUE1, VALUE2)                                            \
+  static_assert(static_cast<int32_t>(VALUE1) == static_cast<int32_t>(VALUE2), \
+                "Enum value mismatch.")
+
+namespace mojo {
+
+// static
+bool StructTraits<device::mojom::SensorConfiguration,
+                  device::PlatformSensorConfiguration>::
+    Read(device::mojom::SensorConfigurationDataView data,
+         device::PlatformSensorConfiguration* out) {
+  // Maximum allowed frequency is capped to 60Hz.
+  if (data.frequency() > 60.0 || data.frequency() <= 0.0) {
+    NOTREACHED();

[dcheng, 2016/07/14 09:24:10]

Nit: this shouldn't be NOTREACHED(), as it's something that can be reached by a
compromised process purposely sending bad messages, or the ipc fuzzer.

I might also recommend DCHECKing that the frequency is in the right range (0 -
60) in the getter, so we'll know if we start violating this condition somehow by
accident on the serialization side.

+    return false;
+  }
+
+  out->set_frequency(data.frequency());
+  return true;
+}
+
+// static asserts to verify that enums are in sync
+CHECK_ENUM(device::ReportingMode::ON_CHANGE,
+           device::mojom::ReportingMode::ON_CHANGE);
+CHECK_ENUM(device::ReportingMode::CONTINUOUS,
+           device::mojom::ReportingMode::CONTINUOUS);
+
+device::mojom::ReportingMode
+EnumTraits<device::mojom::ReportingMode, device::ReportingMode>::ToMojom(
+    device::ReportingMode reporting_mode) {
+  switch (reporting_mode) {
+    case device::ReportingMode::ON_CHANGE:
+      return device::mojom::ReportingMode::ON_CHANGE;
+    case device::ReportingMode::CONTINUOUS:
+      return device::mojom::ReportingMode::CONTINUOUS;
+  }
+
+  NOTREACHED();
+  return device::mojom::ReportingMode::ON_CHANGE;
+}
+
+// static
+bool EnumTraits<device::mojom::ReportingMode, device::ReportingMode>::FromMojom(
+    device::mojom::ReportingMode input,
+    device::ReportingMode* out) {
+  switch (input) {
+    case device::mojom::ReportingMode::ON_CHANGE:
+      *out = device::ReportingMode::ON_CHANGE;
+      return true;
+    case device::mojom::ReportingMode::CONTINUOUS:
+      *out = device::ReportingMode::CONTINUOUS;
+      return true;
+  }
+
+  NOTREACHED();
+  return false;
+}
+
+// static asserts to verify that enums are in sync
+CHECK_ENUM(device::SensorType::FIRST, device::mojom::SensorType::FIRST);
+CHECK_ENUM(device::SensorType::AMBIENT_LIGHT,
+           device::mojom::SensorType::AMBIENT_LIGHT);
+CHECK_ENUM(device::SensorType::PROXIMITY, device::mojom::SensorType::PROXIMITY);
+CHECK_ENUM(device::SensorType::ACCELEROMETER,
+           device::mojom::SensorType::ACCELEROMETER);
+CHECK_ENUM(device::SensorType::GYROSCOPE, device::mojom::SensorType::GYROSCOPE);
+CHECK_ENUM(device::SensorType::PRESSURE, device::mojom::SensorType::PRESSURE);
+CHECK_ENUM(device::SensorType::LAST, device::mojom::SensorType::LAST);
+
+// static
+device::mojom::SensorType
+EnumTraits<device::mojom::SensorType, device::SensorType>::ToMojom(
+    device::SensorType sensor_type) {
+  switch (sensor_type) {
+    case device::SensorType::AMBIENT_LIGHT:
+      return device::mojom::SensorType::AMBIENT_LIGHT;
+    case device::SensorType::PROXIMITY:
+      return device::mojom::SensorType::PROXIMITY;
+    case device::SensorType::ACCELEROMETER:
+      return device::mojom::SensorType::ACCELEROMETER;
+    case device::SensorType::GYROSCOPE:
+      return device::mojom::SensorType::GYROSCOPE;
+    case device::SensorType::PRESSURE:
+      return device::mojom::SensorType::PRESSURE;
+  }
+
+  NOTREACHED();
+  return device::mojom::SensorType::AMBIENT_LIGHT;
+}
+
+// static
+bool EnumTraits<device::mojom::SensorType, device::SensorType>::FromMojom(
+    device::mojom::SensorType input,
+    device::SensorType* out) {
+  switch (input) {
+    case device::mojom::SensorType::AMBIENT_LIGHT:
+      *out = device::SensorType::AMBIENT_LIGHT;
+      return true;
+    case device::mojom::SensorType::PROXIMITY:
+      *out = device::SensorType::PROXIMITY;
+      return true;
+    case device::mojom::SensorType::ACCELEROMETER:
+      *out = device::SensorType::ACCELEROMETER;
+      return true;
+    case device::mojom::SensorType::GYROSCOPE:
+      *out = device::SensorType::GYROSCOPE;
+      return true;
+    case device::mojom::SensorType::PRESSURE:
+      *out = device::SensorType::PRESSURE;
+      return true;
+  }
+
+  NOTREACHED();
+  return false;
+}
+
+}  // namespace mojo