internet/podcasts: Fix crash when updating podcasts.

When a podcast is updated and the number of visible items is set in the
podcast settings, child items that disappear from the view, and are
deleted, are still referenced by the database id map.

Move the removal code from SubscriptionRemoved to a common method and
use that for this case.

src/internet/podcasts/podcastservice.cpp

@@ -395,6 +395,20 @@ QStandardItem* PodcastService::CreatePodcastItem(const Podcast& podcast) {
   return item;
 }
 
+void PodcastService::RemovePodcastItem(QStandardItem* item) {
+  // Remove any episode ID -> item mappings for the episodes in this podcast.
+  for (int i = 0; i < item->rowCount(); ++i) {
+    QStandardItem* episode_item = item->child(i);
+    const int episode_id =
+        episode_item->data(Role_Episode).value<PodcastEpisode>().database_id();
+
+    episodes_by_database_id_.remove(episode_id);
+  }
+
+  // Remove this podcast's row
+  model_->removeRow(item->row());
+}
+
 QStandardItem* PodcastService::CreatePodcastEpisodeItem(
     const PodcastEpisode& episode) {
   QStandardItem* item = new QStandardItem;
@@ -621,18 +635,7 @@ void PodcastService::SubscriptionAdded(const Podcast& podcast) {
 void PodcastService::SubscriptionRemoved(const Podcast& podcast) {
   QStandardItem* item = podcasts_by_database_id_.take(podcast.database_id());
   if (item) {
-    // Remove any episode ID -> item mappings for the episodes in this podcast.
+    RemovePodcastItem(item);
-    for (int i = 0; i < item->rowCount(); ++i) {
-      QStandardItem* episode_item = item->child(i);
-      const int episode_id = episode_item->data(Role_Episode)
-                                 .value<PodcastEpisode>()
-                                 .database_id();
-
-      episodes_by_database_id_.remove(episode_id);
-    }
-
-    // Remove this episode's row
-    model_->removeRow(item->row());
   }
 }
 
@@ -859,6 +862,6 @@ void PodcastService::ReloadPodcast(const Podcast& podcast) {
   }
   QStandardItem* item = podcasts_by_database_id_[podcast.database_id()];
 
-  model_->invisibleRootItem()->removeRow(item->row());
+  RemovePodcastItem(item);
   model_->invisibleRootItem()->appendRow(CreatePodcastItem(podcast));
 }

src/internet/podcasts/podcastservice.h

@@ -119,6 +119,7 @@ class PodcastService : public InternetService {
 
   QStandardItem* CreatePodcastItem(const Podcast& podcast);
   QStandardItem* CreatePodcastEpisodeItem(const PodcastEpisode& episode);
+  void RemovePodcastItem(QStandardItem* item);
 
   QModelIndex MapToMergedModel(const QModelIndex& index) const;