Move BackgroundTaskGroup away from the platform

BackgroundTaskGroup, in fact, doesn't work as expected, e.g. it doesn't
allow to restart a cherry-pick ever again, once a previous queue failed
with an error.

It should probably be substituted by BackgroundTaskQueue.

plugins/svn4idea/src/org/jetbrains/idea/svn/BackgroundTaskGroup.java

@@ -1,19 +1,5 @@
-/*
- * Copyright 2000-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.intellij.openapi.vcs.actions;
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.idea.svn;
 
 import com.intellij.openapi.application.ModalityState;
 import com.intellij.openapi.diagnostic.Logger;
@@ -34,7 +20,10 @@ import static com.intellij.util.containers.ContainerUtil.createLockFreeCopyOnWri
 
 /**
  * Provides common cancellation and error handling behaviour for group of dependent tasks.
+ *
+ * @deprecated use {@link BackgroundTaskQueue}
  */
+@Deprecated
 public class BackgroundTaskGroup extends BackgroundTaskQueue {
 
   private static final Logger LOG = Logger.getInstance(BackgroundTaskGroup.class);

plugins/svn4idea/src/org/jetbrains/idea/svn/integrate/QuickMerge.java

@@ -19,7 +19,7 @@ import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.progress.Task;
 import com.intellij.openapi.util.io.FileUtil;
-import com.intellij.openapi.vcs.actions.BackgroundTaskGroup;
+import org.jetbrains.idea.svn.BackgroundTaskGroup;
 import com.intellij.util.concurrency.Semaphore;
 import org.jetbrains.annotations.CalledInAny;
 import org.jetbrains.annotations.CalledInAwt;

plugins/svn4idea/src/org/jetbrains/idea/svn/treeConflict/MergeFromTheirsResolver.java

@@ -33,7 +33,7 @@ import com.intellij.openapi.ui.Messages;
 import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.util.ThrowableComputable;
 import com.intellij.openapi.vcs.*;
-import com.intellij.openapi.vcs.actions.BackgroundTaskGroup;
+import org.jetbrains.idea.svn.BackgroundTaskGroup;
 import com.intellij.openapi.vcs.changes.*;
 import com.intellij.openapi.vcs.changes.committed.CommittedChangesTreeBrowser;
 import com.intellij.openapi.vcs.changes.patch.ApplyPatchDifferentiatedDialog;