allow to shelve changes from p4 offline mode (IDEA-69121)

platform/vcs-api/src/com/intellij/openapi/vcs/checkin/BeforeCheckinDialogHandler.java

@@ -1,13 +1,17 @@
 package com.intellij.openapi.vcs.checkin;
 
+import com.intellij.openapi.vcs.changes.CommitExecutor;
+
 /**
  * @author irengrig
  *         Date: 5/24/11
  *         Time: 7:23 PM
  */
-public interface BeforeCheckinDialogHandler {
+public abstract class BeforeCheckinDialogHandler {
   /**
    * @return false to cancel commit
+   * @param executors
+   * @param showVcsCommit
    */
-  boolean beforeCommitDialogShownCallback();
+  public abstract boolean beforeCommitDialogShownCallback(Iterable<CommitExecutor> executors, boolean showVcsCommit);
 }

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/ui/CommitChangeListDialog.java

@@ -143,8 +143,8 @@ public class CommitChangeListDialog extends DialogWrapper implements CheckinProj
       CheckinHandlersManager.getInstance().getMatchingVcsFactories(Arrays.<AbstractVcs>asList(allActiveVcss));
     for (BaseCheckinHandlerFactory factory : factoryList) {
       final BeforeCheckinDialogHandler handler = factory.createSystemReadyHandler(project);
-      if (handler != null) {
-        if (! handler.beforeCommitDialogShownCallback()) return false;
+      if (handler != null && !handler.beforeCommitDialogShownCallback(Collections.unmodifiableList(executors), showVcsCommit)) {
+        return false;
       }
     }