Reduce FOR_EACH_OBSERVER macro usage in chrome/browser

chrome/browser/media/router/presentation_service_delegate_impl.cc

Index: chrome/browser/media/router/presentation_service_delegate_impl.cc
diff --git a/chrome/browser/media/router/presentation_service_delegate_impl.cc b/chrome/browser/media/router/presentation_service_delegate_impl.cc
index 415974da2ed01e52df551f1e537c9334d256e409..0a40a5b3346a2fcb5d13b3d9513211d0e0366b9e 100644
--- a/chrome/browser/media/router/presentation_service_delegate_impl.cc
+++ b/chrome/browser/media/router/presentation_service_delegate_impl.cc
@@ -622,9 +622,8 @@ void PresentationFrameManager::ClearDefaultPresentationRequest() {
     return;
 
   default_presentation_request_.reset();
-  FOR_EACH_OBSERVER(
-      PresentationServiceDelegateImpl::DefaultPresentationRequestObserver,
-      default_presentation_request_observers_, OnDefaultPresentationRemoved());
+  for (auto& observer : default_presentation_request_observers_)
+    observer.OnDefaultPresentationRemoved();
 }
 
 bool PresentationFrameManager::IsMainFrame(
@@ -641,10 +640,8 @@ void PresentationFrameManager::SetDefaultPresentationRequest(
 
   default_presentation_request_.reset(
       new PresentationRequest(default_presentation_request));
-  FOR_EACH_OBSERVER(
-      PresentationServiceDelegateImpl::DefaultPresentationRequestObserver,
-      default_presentation_request_observers_,
-      OnDefaultPresentationChanged(*default_presentation_request_));
+  for (auto& observer : default_presentation_request_observers_)
+    observer.OnDefaultPresentationChanged(*default_presentation_request_);
 }
 
 void PresentationFrameManager::SetMediaRouterForTest(MediaRouter* router) {