[file-history] add default implementation to VcsHistorySession#getHistoryAsTreeProvider

GitOrigin-RevId: 8d9fab7cf1d9570c10f3646b9c91dcd052b514b1

platform/vcs-api/src/com/intellij/openapi/vcs/history/VcsHistorySession.java

@@ -24,10 +24,12 @@ public interface VcsHistorySession {
   VcsRevisionNumber getCurrentRevisionNumber();
   boolean isCurrentRevision(VcsRevisionNumber rev);
   boolean shouldBeRefreshed();
-
   boolean isContentAvailable(VcsFileRevision revision);
-  @Nullable
-  HistoryAsTreeProvider getHistoryAsTreeProvider();
   // i.e. is history for local file (opposite - history for some URL)
   boolean hasLocalSource();
+
+  @Nullable
+  default HistoryAsTreeProvider getHistoryAsTreeProvider() {
+    return null;
+  }
 }

plugins/git4idea/src/git4idea/history/GitHistoryProvider.java

@@ -180,11 +180,6 @@ public final class GitHistoryProvider implements VcsHistoryProviderEx,
       }
     }
 
-    @Override
-    public HistoryAsTreeProvider getHistoryAsTreeProvider() {
-      return null;
-    }
-
     @Override
     public VcsHistorySession copy() {
       return createSession(myFilePath, getRevisionList(), getCurrentRevisionNumber());

plugins/hg4idea/src/org/zmlx/hg4idea/provider/HgHistoryProvider.java

@@ -118,11 +118,6 @@ public class HgHistoryProvider implements VcsHistoryProvider {
         return new HgWorkingCopyRevisionsCommand(myProject).parents(vcsRoot, filePath).first;
       }
 
-      @Override
-      public HistoryAsTreeProvider getHistoryAsTreeProvider() {
-        return null;
-      }
-
       @Override
       public VcsHistorySession copy() {
         return createAppendableSession(vcsRoot, filePath, getRevisionList(), getCurrentRevisionNumber());

plugins/svn4idea/src/org/jetbrains/idea/svn/history/SvnHistorySession.java

@@ -30,11 +30,6 @@ public class SvnHistorySession extends VcsAbstractHistorySession {
     }
   }
 
-  @Override
-  public HistoryAsTreeProvider getHistoryAsTreeProvider() {
-    return null;
-  }
-
   @Override
   @Nullable
   public VcsRevisionNumber calcCurrentRevisionNumber() {