don't expose specific type in API

java/java-impl/src/com/intellij/psi/ClassFileViewProvider.java

@@ -56,7 +56,8 @@ public class ClassFileViewProvider extends SingleRootFileViewProvider {
   }
 
   @NotNull
-  public SingleRootFileViewProvider createCopy(final LightVirtualFile copy) {
+  @Override
+  public SingleRootFileViewProvider createCopy(final VirtualFile copy) {
     return new ClassFileViewProvider(getManager(), copy, false);
   }
 }

platform/lang-api/src/com/intellij/psi/FileViewProvider.java

@@ -19,7 +19,6 @@ import com.intellij.lang.Language;
 import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.util.UserDataHolder;
 import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.testFramework.LightVirtualFile;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -81,5 +80,5 @@ public interface FileViewProvider extends Cloneable, UserDataHolder {
   boolean isLockedByPsiOperations();
 
   @NotNull
-  FileViewProvider createCopy(LightVirtualFile copy);
+  FileViewProvider createCopy(VirtualFile copy);
 }

platform/lang-impl/src/com/intellij/psi/DummyHolderViewProvider.java

@@ -141,7 +141,8 @@ public class DummyHolderViewProvider extends UserDataHolderBase implements FileV
   }
 
   @NotNull
-  public FileViewProvider createCopy(final LightVirtualFile copy) {
+  @Override
+  public FileViewProvider createCopy(final VirtualFile copy) {
     throw new RuntimeException("Clone is not supported for DummyHolderProviders. Use DummyHolder clone directly.");
   }
 

platform/lang-impl/src/com/intellij/psi/MultiplePsiFilesPerDocumentFileViewProvider.java

@@ -123,7 +123,8 @@ public abstract class MultiplePsiFilesPerDocumentFileViewProvider extends Single
   }
 
   @NotNull
-  public final MultiplePsiFilesPerDocumentFileViewProvider createCopy(final LightVirtualFile fileCopy) {
+  @Override
+  public final MultiplePsiFilesPerDocumentFileViewProvider createCopy(final VirtualFile fileCopy) {
     final MultiplePsiFilesPerDocumentFileViewProvider copy = cloneInner(fileCopy);
     copy.myOriginal = myOriginal == null ? this : myOriginal;
     return copy;

platform/lang-impl/src/com/intellij/psi/SingleRootFileViewProvider.java

@@ -337,7 +337,8 @@ public class SingleRootFileViewProvider extends UserDataHolderBase implements Fi
   }
 
   @NotNull
-  public SingleRootFileViewProvider createCopy(final LightVirtualFile copy) {
+  @Override
+  public SingleRootFileViewProvider createCopy(final VirtualFile copy) {
     return new SingleRootFileViewProvider(getManager(), copy, false, myBaseLanguage);
   }