Module::getImportedModules can now get public, private, or all imports.

...whereas before the only options were "public" and "all".

No functionality change.

Swift SVN r13849

include/swift/Serialization/SerializedModuleLoader.h

@@ -166,7 +166,7 @@ public:
 
   virtual void
   getImportedModules(SmallVectorImpl<Module::ImportedModule> &imports,
-                     bool includePrivate) const override;
+                     Module::ImportFilter filter) const override;
 
   virtual void
   collectLinkLibraries(Module::LinkLibraryCallback callback) const override;