Revision API: add cherry pick method

This change adds cherry pick function to the Revision API:

  @Inject GerritApi gApi;

  [...]

  Project.NameKey project = ...
  String changeId = ...
  String resvision = ...

  CherryPickInput in = new CherryPickInput();
  in.destination = "foo";
  gApi.projects()
      .name(project.get())
      .branch(in.destination)
      .create(new BranchInput());
  gApi.projects()
      .name(project.get())
      .branch(in.destination)
      .create(new BranchInput());
  ChangeApi cApi = gApi.changes()
      .id(changeId)
      .revision(resvision)
      .cherryPick(in);
  cApi.current()
      .review(approve());
  cApi.current()
      .submit();

Change-Id: Ie291a824720bc1e81c8636773e3a570778383953

gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java

@@ -15,10 +15,14 @@
 package com.google.gerrit.server.api.changes;
 
 import com.google.gerrit.common.errors.EmailException;
+import com.google.gerrit.extensions.api.changes.ChangeApi;
+import com.google.gerrit.extensions.api.changes.Changes;
+import com.google.gerrit.extensions.api.changes.CherryPickInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.api.changes.RevisionApi;
 import com.google.gerrit.extensions.api.changes.SubmitInput;
 import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.server.change.CherryPick;
 import com.google.gerrit.server.change.DeleteDraftPatchSet;
 import com.google.gerrit.server.change.PostReview;
 import com.google.gerrit.server.change.Rebase;
@@ -36,6 +40,8 @@ class RevisionApiImpl implements RevisionApi {
     RevisionApiImpl create(RevisionResource r);
   }
 
+  private final Changes changes;
+  private final Provider<CherryPick> cherryPick;
   private final Provider<DeleteDraftPatchSet> deleteDraft;
   private final Provider<Rebase> rebase;
   private final Provider<PostReview> review;
@@ -43,11 +49,15 @@ class RevisionApiImpl implements RevisionApi {
   private final RevisionResource revision;
 
   @Inject
-  RevisionApiImpl(Provider<DeleteDraftPatchSet> deleteDraft,
+  RevisionApiImpl(Changes changes,
+      Provider<CherryPick> cherryPick,
+      Provider<DeleteDraftPatchSet> deleteDraft,
       Provider<Rebase> rebase,
       Provider<PostReview> review,
       Provider<Submit> submit,
       @Assisted RevisionResource r) {
+    this.changes = changes;
+    this.cherryPick = cherryPick;
     this.deleteDraft = deleteDraft;
     this.rebase = rebase;
     this.review = review;
@@ -96,13 +106,26 @@ class RevisionApiImpl implements RevisionApi {
   }
 
   @Override
-  public void rebase() throws RestApiException {
+  public ChangeApi rebase() throws RestApiException {
     try {
-      rebase.get().apply(revision, null);
+      return changes.id(rebase.get().apply(revision, null)._number);
     } catch (OrmException e) {
       throw new RestApiException("Cannot rebase ps", e);
     } catch (EmailException e) {
       throw new RestApiException("Cannot rebase ps", e);
     }
   }
+
+  @Override
+  public ChangeApi cherryPick(CherryPickInput in) throws RestApiException {
+    try {
+      return changes.id(cherryPick.get().apply(revision, in)._number);
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot cherry pick", e);
+    } catch (EmailException e) {
+      throw new RestApiException("Cannot cherry pick", e);
+    } catch (IOException e) {
+      throw new RestApiException("Cannot cherry pick", e);
+    }
+  }
 }

gerrit-server/src/main/java/com/google/gerrit/server/change/CherryPick.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.server.change;
 
 import com.google.gerrit.common.errors.EmailException;
+import com.google.gerrit.extensions.api.changes.CherryPickInput;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
@@ -25,7 +26,6 @@ import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.change.ChangeJson.ChangeInfo;
-import com.google.gerrit.server.change.CherryPick.Input;
 import com.google.gerrit.server.git.MergeException;
 import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.project.InvalidChangeOperationException;
@@ -37,17 +37,12 @@ import com.google.inject.Provider;
 
 import java.io.IOException;
 
-class CherryPick implements RestModifyView<RevisionResource, Input>,
+public class CherryPick implements RestModifyView<RevisionResource, CherryPickInput>,
     UiAction<RevisionResource> {
   private final Provider<ReviewDb> dbProvider;
   private final Provider<CherryPickChange> cherryPickChange;
   private final ChangeJson json;
 
-  static class Input {
-    String message;
-    String destination;
-  }
-
   @Inject
   CherryPick(Provider<ReviewDb> dbProvider,
       Provider<CherryPickChange> cherryPickChange,
@@ -58,7 +53,7 @@ class CherryPick implements RestModifyView<RevisionResource, Input>,
   }
 
   @Override
-  public ChangeInfo apply(RevisionResource revision, Input input)
+  public ChangeInfo apply(RevisionResource revision, CherryPickInput input)
       throws AuthException, BadRequestException, ResourceConflictException,
       ResourceNotFoundException, OrmException, IOException, EmailException {
     final ChangeControl control = revision.getControl();