WaveClip does not depend on ondemand files besides ODTaskThread...

... Lifting the specification of factory function arguments for Sequence even
higher

This frees ODPCMAliasBlockFile from cycles

src/WaveClip.h

@@ -25,6 +25,8 @@
 #include <vector>
 
 class BlockArray;
+class BlockFile;
+using BlockFilePtr = std::shared_ptr<BlockFile>;
 class DirManager;
 class Envelope;
 class ProgressDialog;
@@ -32,6 +34,7 @@ class Sequence;
 class SpectrogramSettings;
 class WaveCache;
 class WaveTrackCache;
+class wxFileNameWrapper;
 
 class SpecCache {
 public:
@@ -281,11 +284,9 @@ public:
    /// Flush must be called after last Append
    void Flush();
 
-   void AppendAlias(const FilePath &fName, sampleCount start,
-                    size_t len, int channel,bool useOD);
-
-   void AppendCoded(const FilePath &fName, sampleCount start,
-                            size_t len, int channel, int decodeType);
+   using BlockFileFactory =
+      std::function< BlockFilePtr( wxFileNameWrapper, size_t /* len */ ) >;
+   void AppendBlockFile( const BlockFileFactory &factory, size_t len);
 
    /// This name is consistent with WaveTrack::Clear. It performs a "Cut"
    /// operation (but without putting the cutted audio to the clipboard)