[jumbo] avoid kEpsilon collisions in //services/device/generic_sensor

There are several kEpsilon constants defined in //services/device/generic_sensor
which conflict in jumbo builds. To avoid this, we can move the definition
to generic_sensor_consts.h.

BUG=794692

Change-Id: Ib31f20957fc8cccab59abb36779fccff9491239e
Reviewed-on: https://chromium-review.googlesource.com/826062Reviewed-by: Mikhail Pozdnyakov <mikhail.pozdnyakov@intel.com>
Commit-Queue: Mikhail Pozdnyakov <mikhail.pozdnyakov@intel.com>
Cr-Commit-Position: refs/heads/master@{#524043}

services/device/generic_sensor/absolute_orientation_euler_angles_fusion_algorithm_using_accelerometer_and_magnetometer_unittest.cc

@@ -17,8 +17,6 @@ namespace device {
 
 namespace {
 
-constexpr double kEpsilon = 1e-8;
-
 class
     AbsoluteOrientationEulerAnglesFusionAlgorithmUsingAccelerometerAndMagnetometerTest
     : public DeviceServiceTestBase {

services/device/generic_sensor/generic_sensor_consts.h

@@ -7,6 +7,10 @@
 
 namespace device {
 
+// If two doubles differ by less than this amount, we can consider them
+// to be effectively equal.
+constexpr double kEpsilon = 1e-8;
+
 // Required for conversion from G/s^2 to m/s^2
 constexpr double kMeanGravity = 9.80665;
 

services/device/generic_sensor/linear_acceleration_fusion_algorithm_using_accelerometer_unittest.cc

@@ -7,14 +7,13 @@
 #include "base/memory/ref_counted.h"
 #include "services/device/device_service_test_base.h"
 #include "services/device/generic_sensor/fake_platform_sensor_fusion.h"
+#include "services/device/generic_sensor/generic_sensor_consts.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace device {
 
 namespace {
 
-constexpr double kEpsilon = 1e-8;
-
 class LinearAccelerationFusionAlgorithmUsingAccelerometerTest
     : public DeviceServiceTestBase {
  public:

services/device/generic_sensor/orientation_euler_angles_fusion_algorithm_using_quaternion_unittest.cc

@@ -7,17 +7,12 @@
 #include "base/memory/ref_counted.h"
 #include "services/device/device_service_test_base.h"
 #include "services/device/generic_sensor/fake_platform_sensor_fusion.h"
+#include "services/device/generic_sensor/generic_sensor_consts.h"
 #include "services/device/generic_sensor/orientation_test_data.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace device {
 
-namespace {
-
-constexpr double kEpsilon = 1e-8;
-
-}  // namespace
-
 class OrientationEulerAnglesFusionAlgorithmUsingQuaternionTest
     : public DeviceServiceTestBase {
  public:

services/device/generic_sensor/orientation_quaternion_fusion_algorithm_using_euler_angles_unittest.cc

@@ -7,17 +7,12 @@
 #include "base/memory/ref_counted.h"
 #include "services/device/device_service_test_base.h"
 #include "services/device/generic_sensor/fake_platform_sensor_fusion.h"
+#include "services/device/generic_sensor/generic_sensor_consts.h"
 #include "services/device/generic_sensor/orientation_test_data.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace device {
 
-namespace {
-
-constexpr double kEpsilon = 1e-8;
-
-}  // namespace
-
 class OrientationQuaternionFusionAlgorithmUsingEulerAnglesTest
     : public DeviceServiceTestBase {
  public:

services/device/generic_sensor/orientation_util.cc

@@ -13,8 +13,6 @@
 
 namespace {
 
-const double kEpsilon = 1e-8;
-
 // Returns orientation angles from a rotation matrix, such that the angles are
 // according to spec http://dev.w3.org/geo/api/spec-source-orientation.html}.
 //
@@ -53,11 +51,12 @@ void ComputeOrientationEulerAnglesInRadiansFromRotationMatrix(
   DCHECK_EQ(9u, r.size());
 
   // Since |r| contains double, directly compare it with 0 won't be accurate,
-  // so here |kEpsilon| is used to check if r[8] and r[6] is close to 0. And
-  // this needs to be done before checking if it is greater or less than 0
-  // since a number close to 0 can be either a positive or negative number.
-  if (std::abs(r[8]) < kEpsilon) {    // r[8] == 0
-    if (std::abs(r[6]) < kEpsilon) {  // r[6] == 0, cos(beta) == 0
+  // so here |device::kEpsilon| is used to check if r[8] and r[6] is close to
+  // 0. And // this needs to be done before checking if it is greater or less
+  // than 0 since a number close to 0 can be either a positive or negative
+  // number.
+  if (std::abs(r[8]) < device::kEpsilon) {    // r[8] == 0
+    if (std::abs(r[6]) < device::kEpsilon) {  // r[6] == 0, cos(beta) == 0
       // gimbal lock discontinuity
       *alpha_in_radians = std::atan2(r[3], r[0]);
       *beta_in_radians = (r[7] > 0) ? base::kPiDouble / 2