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

content/renderer/device_sensors/device_light_event_pump.cc

Index: content/renderer/device_sensors/device_light_event_pump.cc
diff --git a/content/renderer/device_sensors/device_light_event_pump.cc b/content/renderer/device_sensors/device_light_event_pump.cc
index ed2161fcb39dd09fa8678bee323fdccff09a7d57..90a8a63369c8e42cf7beb39c287dd3f96226a5fe 100644
--- a/content/renderer/device_sensors/device_light_event_pump.cc
+++ b/content/renderer/device_sensors/device_light_event_pump.cc
@@ -6,13 +6,14 @@
 
 #include "base/time/time.h"
 #include "content/public/renderer/render_thread.h"
+#include "device/generic_sensor/shared/device_sensors_consts.h"
 #include "third_party/WebKit/public/platform/WebDeviceLightListener.h"
 
 namespace {
 // Default rate for firing of DeviceLight events.
-const int kDefaultLightPumpFrequencyHz = 5;
 const int kDefaultLightPumpDelayMicroseconds =
-    base::Time::kMicrosecondsPerSecond / kDefaultLightPumpFrequencyHz;
+    base::Time::kMicrosecondsPerSecond /
+    device::kDefaultAmbientLightFrequencyHz;
 }  // namespace
 
 namespace content {