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

device/generic_sensor/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")  # For generate_jni().
 }
 
 component("generic_sensor") {
   output_name = "generic_sensor"
   sources = [
     "generic_sensor_consts.h",
-    "linux/platform_sensor_utils_linux.cc",
-    "linux/platform_sensor_utils_linux.h",
     "linux/sensor_data_linux.cc",
     "linux/sensor_data_linux.h",
     "platform_sensor.cc",
     "platform_sensor.h",
     "platform_sensor_ambient_light_mac.cc",
     "platform_sensor_ambient_light_mac.h",
     "platform_sensor_android.cc",
     "platform_sensor_android.h",
     "platform_sensor_linux.cc",
     "platform_sensor_linux.h",
     "platform_sensor_provider.cc",
     "platform_sensor_provider.h",
     "platform_sensor_provider_android.cc",
     "platform_sensor_provider_android.h",
     "platform_sensor_provider_base.cc",
     "platform_sensor_provider_base.h",
-    "platform_sensor_provider_linux.cc",
-    "platform_sensor_provider_linux.h",
     "platform_sensor_provider_mac.cc",
     "platform_sensor_provider_mac.h",
     "platform_sensor_provider_win.cc",
     "platform_sensor_provider_win.h",
+    "platform_sensor_reader_linux.cc",
+    "platform_sensor_reader_linux.h",
     "platform_sensor_reader_win.cc",
     "platform_sensor_reader_win.h",
     "platform_sensor_win.cc",
     "platform_sensor_win.h",
     "sensor_impl.cc",
     "sensor_impl.h",
     "sensor_provider_impl.cc",
     "sensor_provider_impl.h",
   ]
 
@@ skipping 11 matching lines @@
 
   if (is_android) {
     sources += [
       "android/sensors_jni_registrar.cc",
       "android/sensors_jni_registrar.h",
     ]
 
     deps += [ ":jni_headers" ]
   }
 
-  if (is_mac || is_linux) {
+  if (is_mac) {
     deps += [ "//device/sensors/public/cpp" ]
-  }
-
-  if (is_mac) {
     libs = [ "IOKit.framework" ]
   }
 
+  if (use_udev) {
+    deps += [
+      "//device/base",
+      "//device/udev_linux",
+    ]
+
+    sources += [
+      "linux/platform_sensor_manager.cc",
+      "linux/platform_sensor_manager.h",
+      "platform_sensor_provider_linux.cc",
+      "platform_sensor_provider_linux.h",
+    ]
+  }
+
   if (is_win) {
     libs = [
       "portabledeviceguids.lib",
       "sensorsapi.lib",
     ]
   }
 }
 
 if (is_android) {
   device_sensors_jni_sources = [
@@ skipping 24 matching lines @@
     "fake_platform_sensor_provider.cc",
     "fake_platform_sensor_provider.h",
   ]
 
   public_deps = [
     ":generic_sensor",
     "//base",
     "//testing/gmock",
   ]
 }