Remove usage of FOR_EACH_OBSERVER macro in ios/

ios/web/active_state_manager_impl.mm

Index: ios/web/active_state_manager_impl.mm
diff --git a/ios/web/active_state_manager_impl.mm b/ios/web/active_state_manager_impl.mm
index d2f3b1edfd4da8a1a3b4fdf2e90d405c676e2193..0fa3cda373ee5e2c486ed4548286bf19b52b6b25 100644
--- a/ios/web/active_state_manager_impl.mm
+++ b/ios/web/active_state_manager_impl.mm
@@ -27,7 +27,8 @@ ActiveStateManagerImpl::ActiveStateManagerImpl(BrowserState* browser_state)
 }
 
 ActiveStateManagerImpl::~ActiveStateManagerImpl() {
-  FOR_EACH_OBSERVER(Observer, observer_list_, WillBeDestroyed());
+  for (auto& observer : observer_list_)
+    observer.WillBeDestroyed();
   DCHECK(!IsActive());
 }
 
@@ -46,9 +47,11 @@ void ActiveStateManagerImpl::SetActive(bool active) {
   active_ = active;
 
   if (active) {
-    FOR_EACH_OBSERVER(Observer, observer_list_, OnActive());
+    for (auto& observer : observer_list_)
+      observer.OnActive();
   } else {
-    FOR_EACH_OBSERVER(Observer, observer_list_, OnInactive());
+    for (auto& observer : observer_list_)
+      observer.OnInactive();
   }
 }