[sensors](CrOS/Linux) Implement Sensor device manager for sensors

device/generic_sensor/platform_sensor_provider.cc

Index: device/generic_sensor/platform_sensor_provider.cc
diff --git a/device/generic_sensor/platform_sensor_provider.cc b/device/generic_sensor/platform_sensor_provider.cc
index ce6a4feeb5b0bd908dec11e9b767537f4516e386..e7749e1805067624df7cbdb38c317bd08e0d8718 100644
--- a/device/generic_sensor/platform_sensor_provider.cc
+++ b/device/generic_sensor/platform_sensor_provider.cc
@@ -10,7 +10,7 @@
 #include "device/generic_sensor/platform_sensor_provider_android.h"
 #elif defined(OS_WIN)
 #include "device/generic_sensor/platform_sensor_provider_win.h"
-#elif defined(OS_LINUX)
+#elif defined(OS_LINUX) && defined(USE_UDEV)
 #include "device/generic_sensor/platform_sensor_provider_linux.h"
 #endif
 
@@ -38,8 +38,10 @@ PlatformSensorProvider* PlatformSensorProvider::GetInstance() {
   return PlatformSensorProviderAndroid::GetInstance();
 #elif defined(OS_WIN)
   return PlatformSensorProviderWin::GetInstance();
-#elif defined(OS_LINUX)
+#elif defined(OS_LINUX) && defined(USE_UDEV)
   return PlatformSensorProviderLinux::GetInstance();
+#else
+  return nullptr;
 #endif
 }