Add RELATIVE_ORIENTATION sensor implementation on macOS to //device/generic_sensor

device/generic_sensor/BUILD.gn

Index: device/generic_sensor/BUILD.gn
diff --git a/device/generic_sensor/BUILD.gn b/device/generic_sensor/BUILD.gn
index f95b0a1b20ca513b3413aa7b44b5c58836e5f0fb..a9023ae544b1d046a6b30e4b199e2814d59431c3 100644
--- a/device/generic_sensor/BUILD.gn
+++ b/device/generic_sensor/BUILD.gn
@@ -23,6 +23,8 @@ component("generic_sensor") {
     "platform_sensor_ambient_light_mac.h",
     "platform_sensor_android.cc",
     "platform_sensor_android.h",
+    "platform_sensor_fusion_relative_orientation.cc",
+    "platform_sensor_fusion_relative_orientation.h",
     "platform_sensor_linux.cc",
     "platform_sensor_linux.h",
     "platform_sensor_provider.cc",
@@ -41,6 +43,10 @@ component("generic_sensor") {
     "platform_sensor_reader_win.h",
     "platform_sensor_win.cc",
     "platform_sensor_win.h",
+    "relative_orientation_fusion_algorithm.cc",
+    "relative_orientation_fusion_algorithm.h",
+    "relative_orientation_fusion_algorithm_using_accelerometer.cc",
+    "relative_orientation_fusion_algorithm_using_accelerometer.h",
     "sensor_impl.cc",
     "sensor_impl.h",
     "sensor_provider_impl.cc",