move item setting to a node flag

app/node/project/folder/folder.cpp

@@ -34,6 +34,8 @@ const QString Folder::kChildInput = QStringLiteral("child_in");
 
 Folder::Folder()
 {
+  SetFlag(kIsItem);
+
   AddInput(kChildInput, NodeValue::kNone, InputFlags(kInputFlagArray | kInputFlagNotKeyframable));
 }
 

app/node/project/folder/folder.h

@@ -86,11 +86,6 @@ public:
     return item_children_;
   }
 
-  virtual bool IsItem() const override
-  {
-    return true;
-  }
-
   int index_of_child(Node* item) const
   {
     return item_children_.indexOf(item);

app/node/project/footage/footage.cpp

@@ -46,6 +46,8 @@ Footage::Footage(const QString &filename) :
   cancelled_(nullptr),
   total_stream_count_(0)
 {
+  SetFlag(kIsItem);
+
   PrependInput(kFilenameInput, NodeValue::kFile, InputFlags(kInputFlagNotConnectable | kInputFlagNotKeyframable));
 
   Clear();

app/node/project/footage/footage.h

@@ -153,11 +153,6 @@ public:
    */
   const QString& decoder() const;
 
-  virtual bool IsItem() const override
-  {
-    return true;
-  }
-
   static QString DescribeVideoStream(const VideoParams& params);
   static QString DescribeAudioStream(const AudioParams& params);
   static QString DescribeSubtitleStream(const SubtitleParams& params);

app/node/project/sequence/sequence.cpp

@@ -34,6 +34,8 @@ const QString Sequence::kTrackInputFormat = QStringLiteral("track_in_%1");
 
 Sequence::Sequence()
 {
+  SetFlag(kIsItem);
+
   // Create TrackList instances
   track_lists_.resize(Track::kCount);
 

app/node/project/sequence/sequence.h

@@ -87,11 +87,6 @@ public:
 
   static const QString kTrackInputFormat;
 
-  virtual bool IsItem() const override
-  {
-    return true;
-  }
-
 protected:
   virtual void InputConnectedEvent(const QString &input, int element, Node *output) override;