Allow to submit topic edit with enter key on editor dialog

When editing the topic name, if the user wants to submit the edit
without entering a message, they have to either mouse click on the
submit button or press tab until the focus is on the submit button
and then press enter.

Add a key handler that allows the topic edit to be submitted by the
user pressing enter when focus is on topic name edit box.

Change-Id: Ia1daf18bf67be311a5e7a55de7467941adfb0498

gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeInfoBlock.java

@@ -31,6 +31,9 @@ import com.google.gerrit.reviewdb.client.Branch;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gwt.event.dom.client.ClickEvent;
 import com.google.gwt.event.dom.client.ClickHandler;
+import com.google.gwt.event.dom.client.KeyCodes;
+import com.google.gwt.event.dom.client.KeyPressEvent;
+import com.google.gwt.event.dom.client.KeyPressHandler;
 import com.google.gwt.user.client.ui.Composite;
 import com.google.gwt.user.client.ui.FlowPanel;
 import com.google.gwt.user.client.ui.Grid;
@@ -170,7 +173,8 @@ public class ChangeInfoBlock extends Composite {
     return fp;
   }
 
-  private class AlterTopicDialog extends CommentedActionDialog<ChangeDetail> {
+  private class AlterTopicDialog extends CommentedActionDialog<ChangeDetail>
+      implements KeyPressHandler {
     TextBox newTopic;
     Change change;
 
@@ -180,6 +184,7 @@ public class ChangeInfoBlock extends Composite {
       change = chg;
 
       newTopic = new TextBox();
+      newTopic.addKeyPressHandler(this);
       setFocusOn(newTopic);
       panel.insert(newTopic, 0);
       panel.insert(new InlineLabel(Util.C.alterTopicLabel()), 0);
@@ -191,8 +196,7 @@ public class ChangeInfoBlock extends Composite {
       newTopic.setText(change.getTopic());
     }
 
-    @Override
-    public void onSend() {
+    private void doTopicEdit() {
       String topic = newTopic.getText();
       ChangeApi.topic(change.getId().get(), topic, getMessageText(),
         new GerritCallback<String>() {
@@ -209,5 +213,18 @@ public class ChangeInfoBlock extends Composite {
           super.onFailure(caught);
         }});
     }
+
+    @Override
+    public void onSend() {
+      doTopicEdit();
+    }
+
+    @Override
+    public void onKeyPress(KeyPressEvent event) {
+      if (event.getSource() == newTopic
+          && event.getNativeEvent().getKeyCode() == KeyCodes.KEY_ENTER) {
+        doTopicEdit();
+      }
+    }
   }
 }