[sensors] [mac] Implement ambient light sensor for macOS

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 0e10af42d21cbe8f266cc1721678fa1dbd7e068c..390edf4461bd75541a77012c0560d7495d0c9acf 100644
--- a/device/generic_sensor/BUILD.gn
+++ b/device/generic_sensor/BUILD.gn
@@ -12,6 +12,8 @@ source_set("generic_sensor") {
   sources = [
     "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_provider.h",
@@ -19,6 +21,8 @@ source_set("generic_sensor") {
     "platform_sensor_provider_base.cc",
     "platform_sensor_provider_base.h",
     "platform_sensor_provider_default.cc",
+    "platform_sensor_provider_mac.cc",
+    "platform_sensor_provider_mac.h",
     "sensor_impl.cc",
     "sensor_impl.h",
     "sensor_provider_impl.cc",
@@ -27,6 +31,7 @@ source_set("generic_sensor") {
 
   deps = [
     "//base",
+    "//device/base/synchronization",
     "//device/generic_sensor/public/interfaces",
   ]
 
@@ -39,6 +44,12 @@ source_set("generic_sensor") {
 
     deps += [ ":jni_headers" ]
   }
+
+  if (is_mac) {
+    sources -= [ "platform_sensor_provider_default.cc" ]
+
+    deps += [ "//device/sensors/public/cpp" ]
+  }
 }
 
 if (is_android) {