Replace FOR_EACH_OBSERVER in c/b/chromeos with range-based for

chrome/browser/chromeos/camera_presence_notifier.cc

Index: chrome/browser/chromeos/camera_presence_notifier.cc
diff --git a/chrome/browser/chromeos/camera_presence_notifier.cc b/chrome/browser/chromeos/camera_presence_notifier.cc
index 2d44dd912f1d1624554797ff2ff325bd5c5f0a40..51ac2687d5bc61ff91d917e2e602347deea24ee6 100644
--- a/chrome/browser/chromeos/camera_presence_notifier.cc
+++ b/chrome/browser/chromeos/camera_presence_notifier.cc
@@ -64,9 +64,8 @@ void CameraPresenceNotifier::OnCameraPresenceCheckDone() {
       CameraDetector::camera_presence() == CameraDetector::kCameraPresent;
   if (is_camera_present != camera_present_on_last_check_) {
     camera_present_on_last_check_ = is_camera_present;
-    FOR_EACH_OBSERVER(Observer,
-                      observers_,
-                      OnCameraPresenceCheckDone(camera_present_on_last_check_));
+    for (auto& observer : observers_)
+      observer.OnCameraPresenceCheckDone(camera_present_on_last_check_);
   }
 }