Reduce FOR_EACH_OBSERVER macro usage in chrome/browser

chrome/browser/media/router/issue_manager.cc

Index: chrome/browser/media/router/issue_manager.cc
diff --git a/chrome/browser/media/router/issue_manager.cc b/chrome/browser/media/router/issue_manager.cc
index d3cb9d4f3b5a18fd30765c7c8eeaa24d20718e2d..53d74c8cd7fc49f9fd2ae3483160a3096fa4d28b 100644
--- a/chrome/browser/media/router/issue_manager.cc
+++ b/chrome/browser/media/router/issue_manager.cc
@@ -95,8 +95,8 @@ void IssueManager::MaybeUpdateTopIssue() {
   const Issue* new_top_issue = nullptr;
 
   if (issues_.empty()) {
-    FOR_EACH_OBSERVER(IssuesObserver, issues_observers_,
-                      OnIssueUpdated(new_top_issue));
+    for (auto& observer : issues_observers_)
+      observer.OnIssueUpdated(new_top_issue);
     return;
   }
 
@@ -114,8 +114,8 @@ void IssueManager::MaybeUpdateTopIssue() {
   // If we've found a new top issue, then report it via the observer.
   if (new_top_issue->id() != top_issue_id_) {
     top_issue_id_ = new_top_issue->id();
-    FOR_EACH_OBSERVER(IssuesObserver, issues_observers_,
-                      OnIssueUpdated(new_top_issue));
+    for (auto& observer : issues_observers_)
+      observer.OnIssueUpdated(new_top_issue);
   }
 }