Edit Assignee Permissions

Permission deciding who is able to edit the assignee of a change.
Besides the users with edit assignee permission change owner, ref owner, and
the currently assigned user are allowed to change the assignee of a change.

Change-Id: I7cbc950c66b3d5f1e931d5f8d985d8112682971f

gerrit-server/src/main/java/com/google/gerrit/server/project/ChangeControl.java

@@ -352,6 +352,16 @@ public class ChangeControl {
     return false;
   }
 
+  /** Is this user assigned to this change? */
+  public boolean isAssignee() {
+    Account.Id currentAssignee = notes.getAssignee();
+    if (currentAssignee != null && getUser().isIdentifiedUser()) {
+      Account.Id id = getUser().getAccountId();
+      return id.equals(currentAssignee);
+    }
+    return false;
+  }
+
   /** Is this user a reviewer for the change? */
   public boolean isReviewer(ReviewDb db) throws OrmException {
     return isReviewer(db, null);
@@ -414,6 +424,13 @@ public class ChangeControl {
     return getRefControl().canForceEditTopicName();
   }
 
+  public boolean canEditAssignee() {
+    return isOwner()
+        || getProjectControl().isOwner()
+        || getRefControl().canEditAssignee()
+        || isAssignee();
+  }
+
   /** Can this user edit the hashtag name? */
   public boolean canEditHashtags() {
     return isOwner() // owner (aka creator) of the change can edit hashtags

gerrit-server/src/main/java/com/google/gerrit/server/project/RefControl.java

@@ -447,6 +447,10 @@ public class RefControl {
     return canPerform(Permission.EDIT_HASHTAGS);
   }
 
+  public boolean canEditAssignee() {
+    return canPerform(Permission.EDIT_ASSIGNEE);
+  }
+
   /** @return true if this user can force edit topic names. */
   public boolean canForceEditTopicName() {
     return canForcePerform(Permission.EDIT_TOPIC_NAME);